Using the responsive text example code and resizing the window multiple times and you’ll see the issue:
https://codepen.io/danielkorte/pen/OJEVRoN
The reason for the issue is split() calls revert() which calls SplitType.revert() which deletes the 'html' cached data so the second run of split() will again call revert() but 'html' will be undefined at that point.