When I use the animation of the transform with skewY setting, the coordinates change. Conversely, skewX animation and no-animation skewY does not change the coordinates (expected behavior). Maybe skewY with animation does not work correctly.
Unexpected coordinates change with the skewY animation:
Bug report
Fiddle
https://jsfiddle.net/pd1u98nk/2/
Explanation
When I use the animation of the transform with skewY setting, the coordinates change. Conversely, skewX animation and no-animation skewY does not change the coordinates (expected behavior). Maybe skewY with animation does not work correctly.
Unexpected coordinates change with the skewY animation:
https://jsfiddle.net/pd1u98nk/2/
Expected coordinates (no-animation skewY updating):
https://jsfiddle.net/och3udyr/
SkewX animation also works correctly (no coordinates change):
https://jsfiddle.net/pd1u98nk/3/