Good call. I just remembered that I updated from Python 3.7 to Python 3.10 (for no particular reason). I have downgraded back to 3.7 - and the problem has gone away. I'm fully updated now.
Stock versions on OctoPi 0.17 (with update to py3) through 1.0.0rc on every update. Additionally 3.7, 3.8, 3.9, 3.10 automatically on CI. 3.7 and 3.9 on my own dev environments.
The issue here though isn't the python version. It's having upgraded the system wide python version and that apparently missing some bits.
sadly i updated my pi from 1.8.0 to the 1.8.1 and now it wont even run and octodash says the pi has timed out. so i need to figure out how to roll back and not being able to get into it .