I've noticed a strange issue: the analyze module stops writing file names for some reason. It first cropped up when I was looking at some logs trying to inspect subframes (by the way, this feature is AMAZING when it works). Last night I noticed that if I examined the current session, it had failed to write the filenames for previous capture points.
I have been running Raspberry PI 4 with Kstars 3.5.5 and indilib 1.9.2 with the same problem. I installed Kstars 3.5.6 and indilib 1.9.3 from sources. Still the same problem.
However, it works on my PC/laptop running Kubuntu 20.04, also on Opensuse Leap 15.3, so it seems to be an environment problem.
I ended up installing Ubuntu Mate on the RPI 4 with the latest Kstars/indilib from repositories, and now it works.
So that may be the quickest/easiest solution for you?
It is definitely in the Kstars log:
[2021-11-21T23:44:14.038 CET DEBG ][ org.kde.kstars.ekos.guide] - Capturing frame...
[2021-11-21T23:44:14.153 CET DEBG ][ org.kde.kstars.indi] - Image received. Mode: "Normal" Size: 23397120
[2021-11-21T23:44:14.192 CET INFO ][ org.kde.kstars.indi] - "FITS" file saved to "/home/hwa/Sessions/M33/M_33/Light/L-Pro/M_33_Light_L-Pro_60_secs_2021-11-21T23-44-14_064.fits"
[2021-11-21T23:44:14.193 CET INFO ][ org.kde.kstars.ekos.capture] - "Download Time: 0.81 s, New Download Time Estimate: 0.45 s."
[2021-11-21T23:44:14.195 CET INFO ][ org.kde.kstars.ekos.capture] - "Received image 64 out of 120."