--- /home/igalia/clopez/webkit/webkit-flatpak/layout-test-results/mathml/opentype/horizontal-munderover-expected.txt
+++ /home/igalia/clopez/webkit/webkit-flatpak/layout-test-results/mathml/opentype/horizontal-munderover-actual.txt
@@ -6,8 +6,8 @@
       RenderBlock {P} at (0,0) size 784x38
         RenderMathMLMath {math} at (0,8) size 48x19
           RenderMathMLRow {mstyle} at (0,0) size 48x19
-            RenderMathMLUnderOver {mover} at (0,0) size 48x12
-              RenderMathMLOperator {mo} at (0,5) size 48x7
+            RenderMathMLUnderOver {mover} at (0,0) size 48x13
+              RenderMathMLOperator {mo} at (0,5) size 48x8
                 RenderBlock (anonymous) at (0,0) size 8x14
                   RenderText {#text} at (0,-44) size 8x106
                     text run at (0,-44) width 8: "\x{23DE}"
@@ -19,19 +19,19 @@
             RenderMathMLUnderOver {mover} at (0,0) size 64x19
               RenderMathMLSpace {mspace} at (0,16) size 64x3 [bgcolor=#FF0000]
               RenderMathMLOperator {mo} at (0,0) size 64x12
-                RenderBlock (anonymous) at (0,0) size 6x11
-                  RenderText {#text} at (0,-33) size 6x80
-                    text run at (0,-33) width 6: "\x{23DE}"
+                RenderBlock (anonymous) at (0,0) size 6x12
+                  RenderText {#text} at (0,-32) size 6x80
+                    text run at (0,-32) width 6: "\x{23DE}"
         RenderText {#text} at (116,13) size 4x17
           text run at (116,13) width 4: " "
-        RenderMathMLMath {math} at (120,13) size 48x16
-          RenderMathMLRow {mstyle} at (0,0) size 48x16
-            RenderMathMLUnderOver {munder} at (0,0) size 48x16
-              RenderMathMLOperator {mo} at (0,0) size 48x6
+        RenderMathMLMath {math} at (120,13) size 48x17
+          RenderMathMLRow {mstyle} at (0,0) size 48x17
+            RenderMathMLUnderOver {munder} at (0,0) size 48x17
+              RenderMathMLOperator {mo} at (0,0) size 48x7
                 RenderBlock (anonymous) at (0,0) size 8x14
                   RenderText {#text} at (0,-44) size 8x106
                     text run at (0,-44) width 8: "\x{23DE}"
-              RenderMathMLSpace {mspace} at (0,13) size 48x3 [bgcolor=#FF0000]
+              RenderMathMLSpace {mspace} at (0,14) size 48x3 [bgcolor=#FF0000]
         RenderText {#text} at (168,13) size 4x17
           text run at (168,13) width 4: " "
         RenderMathMLMath {math} at (172,8) size 64x31
@@ -39,54 +39,54 @@
             RenderMathMLUnderOver {munderover} at (0,0) size 64x31
               RenderMathMLSpace {mspace} at (0,16) size 64x3 [bgcolor=#FF0000]
               RenderMathMLOperator {mo} at (0,18) size 64x12
-                RenderBlock (anonymous) at (0,0) size 6x11
-                  RenderText {#text} at (0,-33) size 6x80
-                    text run at (0,-33) width 6: "\x{23DE}"
+                RenderBlock (anonymous) at (0,0) size 6x12
+                  RenderText {#text} at (0,-32) size 6x80
+                    text run at (0,-32) width 6: "\x{23DE}"
               RenderMathMLOperator {mo} at (0,0) size 64x12
-                RenderBlock (anonymous) at (0,0) size 6x11
-                  RenderText {#text} at (0,-33) size 6x80
-                    text run at (0,-33) width 6: "\x{23DE}"
+                RenderBlock (anonymous) at (0,0) size 6x12
+                  RenderText {#text} at (0,-32) size 6x80
+                    text run at (0,-32) width 6: "\x{23DE}"
         RenderText {#text} at (236,13) size 4x17
           text run at (236,13) width 4: " "
-        RenderMathMLMath {math} at (240,0) size 48x29
-          RenderMathMLRow {mstyle} at (0,0) size 48x29
-            RenderMathMLUnderOver {munderover} at (0,0) size 48x29
-              RenderMathMLOperator {mo} at (0,12) size 48x7
+        RenderMathMLMath {math} at (240,0) size 48x30
+          RenderMathMLRow {mstyle} at (0,0) size 48x30
+            RenderMathMLUnderOver {munderover} at (0,0) size 48x30
+              RenderMathMLOperator {mo} at (0,12) size 48x8
                 RenderBlock (anonymous) at (0,0) size 8x14
                   RenderText {#text} at (0,-44) size 8x106
                     text run at (0,-44) width 8: "\x{23DE}"
-              RenderMathMLSpace {mspace} at (0,26) size 48x3 [bgcolor=#FF0000]
-              RenderMathMLOperator {mo} at (0,0) size 48x6
-                RenderBlock (anonymous) at (0,0) size 6x11
-                  RenderText {#text} at (0,-33) size 6x80
-                    text run at (0,-33) width 6: "\x{23DE}"
+              RenderMathMLSpace {mspace} at (0,27) size 48x3 [bgcolor=#FF0000]
+              RenderMathMLOperator {mo} at (0,0) size 48x5
+                RenderBlock (anonymous) at (0,0) size 6x12
+                  RenderText {#text} at (0,-32) size 6x80
+                    text run at (0,-32) width 6: "\x{23DE}"
         RenderText {#text} at (288,13) size 4x17
           text run at (288,13) width 4: " "
         RenderMathMLMath {math} at (292,8) size 48x20
           RenderMathMLRow {mstyle} at (0,0) size 48x20
             RenderMathMLUnderOver {munderover} at (0,0) size 48x20
-              RenderMathMLOperator {mo} at (0,5) size 48x7
+              RenderMathMLOperator {mo} at (0,5) size 48x8
                 RenderBlock (anonymous) at (0,0) size 8x14
                   RenderText {#text} at (0,-44) size 8x106
                     text run at (0,-44) width 8: "\x{23DE}"
-              RenderMathMLOperator {mo} at (0,13) size 48x7
-                RenderBlock (anonymous) at (0,0) size 6x11
-                  RenderText {#text} at (0,-33) size 6x80
-                    text run at (0,-33) width 6: "\x{23DE}"
+              RenderMathMLOperator {mo} at (0,14) size 48x6
+                RenderBlock (anonymous) at (0,0) size 6x12
+                  RenderText {#text} at (0,-32) size 6x80
+                    text run at (0,-32) width 6: "\x{23DE}"
               RenderMathMLSpace {mspace} at (0,0) size 48x2 [bgcolor=#FF0000]
         RenderText {#text} at (340,13) size 4x17
           text run at (340,13) width 4: " "
         RenderMathMLMath {math} at (344,8) size 48x20
           RenderMathMLRow {mstyle} at (0,0) size 48x20
             RenderMathMLUnderOver {munder} at (0,0) size 48x20
-              RenderMathMLUnderOver {mover} at (0,0) size 48x12
-                RenderMathMLOperator {mo} at (0,5) size 48x7
+              RenderMathMLUnderOver {mover} at (0,0) size 48x13
+                RenderMathMLOperator {mo} at (0,5) size 48x8
                   RenderBlock (anonymous) at (0,0) size 8x14
                     RenderText {#text} at (0,-44) size 8x106
                       text run at (0,-44) width 8: "\x{23DE}"
                 RenderMathMLSpace {mspace} at (0,0) size 48x2 [bgcolor=#FF0000]
-              RenderMathMLOperator {mo} at (0,13) size 48x7
-                RenderBlock (anonymous) at (0,0) size 6x11
-                  RenderText {#text} at (0,-33) size 6x80
-                    text run at (0,-33) width 6: "\x{23DE}"
+              RenderMathMLOperator {mo} at (0,14) size 48x6
+                RenderBlock (anonymous) at (0,0) size 6x12
+                  RenderText {#text} at (0,-32) size 6x80
+                    text run at (0,-32) width 6: "\x{23DE}"
         RenderText {#text} at (0,0) size 0x0