I have found that recently OctoPrint loses control of the Z axis after completing a print job. This behavior seems to have appeared after the last round of updates were installed . The general scenario is that I can kick off a print job and it will print. Upon completion, my printer is setup to shutoff after two minutes (the printer, not the Pi/Octoprint). Should I want to print another item, I can turn the printer back on through OctoPrint, however I will not be able to home the Z axis nor move it from the control tab - X/Y homing and controls work as normal. If I do kick off a print job, it will print in the air at whichever height it was left at from the previous print.
The issue goes away simply by restarting OctoPrint (not the Pi and not the printer). Once OctoPrint is restarted, control of the Z axis returns and can be homed and moved via the control tab as expected. Once the print completes, the same be havior will be exhibited.
I plan to run OctoPrint in safe mode to rule out any plugins, but have had some orders to print and thus not had the time available to troubleshoot further. I am not sure if anyone else has encountered this issue before - I did not see anything when searching through the other posts - but perhaps someone already knows the answer.
OctoPrint Version: 1.3.11 (stable release)
Printer: AM8 (metal frame upgraded Anet A8)
Firmware: Marlin 1.1.8