Recently I upgraded my copy of Chrome to 69 (from 63). After doing so the
application I was working on (Django, Bootstrap, etc) started to show an odd
problem: buttons styled with Bootstrap's "btn" class would fade in. This was
most noticeable with those that had a solid colour (so btn-primary, for
example).
The thing was, this wasn't on every page. Some pages were fine. After narrowing things down a little I found that any page that had a script lower down the page didn't display the problem. This, in turn, resulted in me finding that if I added this:
<script></script>to the bottom of every body, the problem went away!
That was just a curious workaround, of course. It wasn't a solution.
After some ore digging I finally narrowed it down to there being a
combination of a form and Bootstrap buttons on the same page. The
resulting index.html which you'll find in this repo is the
minimal version of the problem.
What I've since found is that it's fine in Incognito mode; this would suggest that it's an issue that also involves one of the extensions I have loaded. A process of elimination has narrowed it down to LastPass.
So.... if I have Chrome 69 (tested on GNU/Linux and macOS), and Bootstrap 4, and a form, and a Bootstrap button, and no script in the body of the page, and I have the LastPass extension loaded.... buttons oddly fade their colour in every time the page loads.