KDE is an international technology team creating user-friendly free and open source software for desktop and portable computing. KDE’s software runs on GNU/Linux, BSD and other operating systems, including Windows.
If you encounter a bug, proceed to https://bugs.kde.org/, check whether it has been reported.
If it hasn't, report it yourself.
PLEASE THINK CAREFULLY BEFORE POSTING HERE.
Developers do not look for reports on social media, so they will not see it and all it does is clutter up the feed.
Since the update, if I snap Firefox to the top the mouse seems to be offset a number of pixels compared to where the actual cursor is. It also affects the content in sites, not just stuff in Firefox.
Edit: Looks like it's not just when it's snapped, but as soon as it passes about the top 90% of the screen. Just took a screenshot, where you can see the cursor is hovering over Other Bookmarks, but it's activating the menu above it.
I found that setting Firefox to fullscreen, then resizing it from there is a bit of a workaround that worked.