I'm Having a bug where it wont let me play a character during a turn, or playing his cards. It does usually reset next round after you PASS. But it's a pain in the ass coz you'll end up losing a fight because of that.
Are there any cards attached to the character, such as stun or halt cards? Stun attachments prevent a character from playing any card type other than movement. Halt attachments prevent a character from playing any movement cards.
I have felt like this and then later noticed what was causing it but never during my massive amount of play hours has this ever happened for no reason.
The next time this happens, please press F1 twice to open the console and check for any errors. You could also type "dumpclientcommands" and report what you see.