Hi! The HTML5 version on Itch.io is still the original version, based on - if I'm not wrong - UE4.11 (!). At the time I fixed a few issues to make it working on Itch.io, and I reported all my findings to Epic here: https://forums.unrealengine.com/t/fixes-to-play-html5-builds-on-itch-io/354708 . It's old stuff (2016), so I'm not sure is still valid now. I hope it will help you.