From IRC:

I have a "bal not ("[xxx]") command which is quite slow. It takes about 20 seconds when it used to only take less than a second.
I just downgraded to version 3.1.3 on Arch Linux and the same command takes less than 1 second. :/

Other command which do not have the "not" command seem to be performing normally.

I'll work on a way a standard way to reproduce, but I thought it was worth reporting in case anyone else is having an issue.