Post/Page Publish/Update button not clickable once I make an edit

Question

I open a page and make an edit and the update button becomes grayed out. I have to copy all page content, refresh the page and paste it back in the page, only then does the update button become clickable. It does update the page so there is no issue with that.

Only when making the initial edit is in not clickable.

Update: I was able to recreate the issue, but not faithfully. It seems to occur when the page is trying to auto save. It would begin to autosave and then hang.

I don't even know where to begin with this one. Has anyone encountered something similar?