It leaves the containers behind when I use it so my container list is polluted with all of the temporary numbered containers. It stops me using it when it can’t cleanly handle itself…

Probably Firefox sync, but most likely the extension. I’ll use it again once it works.

There are options to define how container numbering is handled. Right in the General Tab. These settings work for me...

Container Number: Reuse available numbers

Delete no longer needed Temporary Containers: After the last tab in it closes

I launch FF in a shell function that first calls BleachBit and calls it again when FF terminates. Not sure if that would help your case but it works for me. The reason I do this from a shell function is to redirect the output of FF console to a ramdisk just in case I needed it but did not have it prior to seeing something odd.