I've been using this setup/rig without any real problems (occasional meridian flip problems, making my new ASI2600MC to work correctly) for well over a year, maybe more.
Had several successful sessions around last New Moon.
Tonight, the Guide Module gave me a real headache.
It was really doing strange things during the calibration step.
-- didn't do anything but claimed that the calibration was successful.
-- would go RA forward for a couple of steps and claim that the calibration was successful.
-- would go RA forward and back but skip DEC and claim that the calibration was successful.
-- after that the guiding was atrocious
-- sometimes the Drift Plot wouldn't show anything at all even though the guider was (badly) guiding.
So, I kept doing and redoing the calibration, rebooting RPI, connecting/disconnecting cables and eventually the calibration went through
and now it guides quite reasonably.
What could be the cause for this?
My guess it's either the FTDI cable (quite new) to the mount or the mount itself (quite old HEQ5) or just a bad connection somewhere.
Using the latest stable INDI/KStars/Ekos. It was the same with Windows and RPI client.