I am currently using a system from Ekos with just ST-7 and CFW8 for indoor experiments.
The specific situation is shown in the attached diagram.

KStars update was pushed today, please update and check if it is still the same issue.

I just updated to KStars 3.6.1 Stable (Build: 2022-10-14T04:48:59Z).
Unfortunately, the situation has not changed.

I had this problem with a QHY filter wheel and the manual filter. I found I had to go into optical train and remove the filter wheel and close, then go back to optical train and set the filter wheel and close and it was OK.

Thanks for your comments.
Based on your experience, it may be that Ekos is waiting for the filter wheel to be flagged to return to its origin.
I immediately opened the lid of the CFW8, shifted the wheel slightly by hand, put the lid back on and connected it to Ekos. When I powered on the wheel, the wheel did indeed spin and return to its origin, but the response on Ekos's part was the same as before.

I need to worry about this some more.

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I just installed Ubuntu MATE 20.04.5 on another laptop and built KStars, INDI and SBIG Parport Special driver.

It is a completely clean system but I am having the exact same problem with the filter operation after connecting to ST-7 and CFW8.

Problem solved!
I applied the newly arrived KStars update and the Ubuntu kernel update, and this combination has made the filter operation from Ekos normal.

KStars
Build: 2022-10-15T12:30:07Z

Ubuntu Kernel
5.15.0-52-generic

The clean system laptop also now works correctly with the kernel update.

I had similar issue with my ZWO EFW and my ASI533MM. I found that restarting the camera driver would then have the filter wheel show up in the camera settings for selection. To restart it just press the power button icon beside the camera description.

After doing this a few times, I haven't had any more problems, but I did also apply the update from the StellarMate app to my RPi.

Thank you.

Two weeks ago I opened the chamber of three ST-7's I have and cleaned the CCD's. When I was about to check that work, the filter turret went haywire.
At that time, there was a system update before I started the checking process and when I tried to operate the camera from KStars, it crashed. I then noticed that there was an update for KStars, and when I updated it, KStars was up and running, but only the filter turret function was malfunctioning.
I did restart the camera driver as the first thing I did. I just happened to notice the button icon.
Then I also noticed that there are posts within this forum that appear to have the exact same symptoms. But no one responded, so I wondered if it was a self-solvable problem.

But since I couldn't figure out the cause of the problem by going through the user configuration files, let alone restarting the camera driver, and since purging and reinstalling KStars and INDI Libraries didn't change the situation, I decided to post it here.

I've tried the behavior in various cases, so reading the settings from the Ekos side right after the start fails, and informing Ekos of the settings from the INDI side is working.
I've also replaced 3 ST-7s with CFW8 and the same problem has reproduced itself, and this morning it was the same with a new ubuntu machine. So I was thinking that this was probably something to do with KStars, INDI SBIG CCD Lib, remnants of the old SBIG universal driver, and their relationship to the system.
Then a new build of KStars and an update of the ubuntu kernel arrived, so I tried them one by one and found that on two ubuntu PCs, once I was satisfied with these updates, the situation became normal.

I'm glad we got it resolved.

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Hello Jasem, I have the same issue. I've updated stellarmate to the last version 1.7.5 and filters are gone in ekos. I have to remove filters in Opticals Train, close it and set filters again. After that filters appear. Kstars does not see filters after connect, select box is disabled. But INDI can see it in CCD Filter settings and I can change it.

I have RPi4, QHY600L+CFW3 connected via 4pin serial. KStars 3.6.3 version, QHY SDK version 22.11.9, in logs I see string "QHY CCD QHY600M-c765284 filter is online.". How to solve this problem?

I actually have this exact issue with QHY268 and tried many hacks to make the driver reports the filter. The problem is that sometimes the SDK itself reports no internal filter wheel detected. If I disconnected and reconnect, it detects fine. Since I control power to the cameras, I noted that I needed to power QHY first for at least 10 seconds before attempting a connection. This alleviated the issue a bit. Btw, this is an old issue that I've had for more than a year and make the QHY SDK should do a better job at detection. Just updated GIT to latest QHY SDK but I don't think the filter wheel issue is addressed.

Thanks for reply. I tried to connect 1-2 minutes after turning on the equipment - it did not help. I also tried to turn off the power of the camera, turn it on again and wait a bit. It doesn't help either. The only thing that helps is removing the filters and re-enabling. Tell me how to get an update from git? It is enough to issue a "sudo apt update && sudo apt upgrade && sudo apt dist-upgrade" command? sorry, not good at linux commands