Most combos with left Ctrl is broken for me on multiple Cinnamon systems. Since that’s the only DE I use I cannot say if it exists outside that. I will say another user also reported Ctrl issues in the latest Stable update thread but did not mention his DE.
I did some digging and previously they said this was a bug in XOrg that had to get patched. But that was in 2018.
On my systems ( multiple ones so multiple keyboards ) if I try to do Ctrl+Shift for example, it does not work. But some things do. Ctrl+Alt left / right works. The majority of my issues are Ctrl+Shift but other things have not worked at times.
In the virtual keyboard I can bring up, when I press left Ctrl it never lights up to recognize it as being hit. Other keys do. But obviously that’s not completely right if Ctrl+Alt+left/right works.
I can use the right Ctrl and that works, but there’s no way I’m going to get used to that after a couple of decades of left Ctrl + something.
In any case, something got borked with using the left Ctrl key in the update.
I will say I’m pretty sure it’s something with Cinnamon. I do have a bug report open with them.
I got home and validated it was still borked on the home desktop. Rebooted to my old drive with an install of Cinnamon and KDE on it that I keep around to test config changes since I don’t care if I break that too much.
It was on Cinnamon 5.4.3. Tested out things and it worked. Validated the same behavior in KDE. Updated and it’s now on 5.4.10. Broken. I logged into KDE and things worked fine there