This might likely be a Qt bug, as there is an infamous bug about losing input on Qt6 apps after suspend, but this issue is a bit different.

I can reproduce it everytime, since a few releases, not really sure how many in fact.

To reproduce I just need that the compiler returns a huge pile of errors, usually with projects that uses templates that's the case, even if you hit stop soon the "Compile Output" keeps getting texts for a while, QtCreator is still responsive, but keyboard input stops working, mouse is however still working, so I can still save my work, but will lose my redo history...

 "Compile Output" pane must be open.

Ok, now that I'm reporting the bug it seems that after a long while (minutes) eventually the keys get delivered, but what is really weird is that the app is totally responsive to the mouse, I can open Settings window and what not, just keyboard events seems to be "low priority" on the event queue..