The picomotor controllers were not working. The software side looked ok, but there was no physical drive signal. The TwinCAT system showed an error message about "nonsensical priority order of the PLC tasks". In the past, we ignored these messages without any problems. After fixing this issue and re-activating the system, it started working again. Not usre if it just needed a restart, or if the priority order has now become important. More investigation needed.