So…
I discovered that if you press the stop button fast enough right after clicking play (a bad habit of mine) you can get stuck in play test mode.
When stuck, clicking the stop button doesn’t work, nor does shift+f5, and I can’t save the file.
I’ve already lost a bunch of progress with this, the workaround I found is copying all the scripts that I changed and pasting them into an older file, together with meshes/anything like that.
Has anyone else ever faced this issue? Is there a fix, or is it an engine bug?