Did you make any changes that you can remember. I also use my one for guiding but its not working.

I only updated the server and client, both x86_64.
And it stopped bugging me (exposure failed, retrying) during guiding and calibration.
last nigth I made a full guided session of 3h without any failure. The behavior of the ASI120MM is
pretty inconsistent. One day it works fine, the next day it fails.

I tried to do shorter exposures than 0.01s and the driver still fails at some point, but the whole system does not seem to crash at the moment. Also, many frames are distorted with short exposures. For longer exposures my setup seem to work fine at the moment. I have still not dared to attach another camera, though...
My system became somewhat stable when I updated to indi 1.3.1. Just updated to the latest today without any change.

Just noticed that when the distorted frames appears, it take a long time before indi is ready again to take a frame. I generally test this by probing

indi_getprop 'ZWO CCD ASI120MC.CCD_EXPOSURE.CCD_EXPOSURE_VALUE'

Under 'good' operation, the fits file appears almost the same time as the above value signals that the exposure is done. When the distorted frames appears, the fits file appears as expected, but the above takes like 10-20s after the fits file appears before it signals that the exposure is done.

Today I dared. I connected by Meade DSI Pro and both cameras were initially chugging along just fine. Then suddently the DSI started to capture distorted frames. I restarted indi and everything worked fine again. Then after a little while, the ASI started to show a lot of totally black frames. Conclusion: It still does not work! I thus went back to one-camera operation.

Would there be any idea in starting two indi-servers using two different ports? One for the ASI alone and one for all other equipment?

On the plus side: I have not experienced a total system crash for several weeks now

Well, ASI replied to me and said USB 2.0 cameras do not work well under LInux. I don't know why, maybe their USB 3.0 cameras are better? It seems there should be enough bandwidth even for USB 2.0 but what do I know.

FYI about releasing the code, Sam from ZWO forum answered :
zwoug.org/viewtopic.php?f=17&t=6668&start=10

Hmmm, my one was working in linux up to the end of November. Whatever they did to the latest SDK has broken it so its not really a hardware 'problem'

Can we just roll back to an earlier SDK that didn't have this issue?

Maybe have an indi_asi_ccd_old driver along the new one?

Odd that it worked with my 5m usb cable and also my 0.5m cable equally well, though the 5m was an active usb cable, not passive.

What do you mean by active usb cable? Is it shielded?