OK, after recovering from the damage done after setting a nickname for the camera, I'm back to figuring out why the camera temperature control isn't working after this update.

As a test, I swapped out SD cards in the RPi and put in an INDIGO one. With this I could connect to the camera and control the temperature. I think this indicates it is not a hardware problem on my end.

As I've said before, it is like the software doesn't think cooling is available on this camera. The On/Off buttons are disabled in the Camera tab. The check mark icon to set the temp isn't disabled but it seems to have no effect.

The software always reports the camera temp as 0. This is probably because it thinks there is no temperature control available.

As a test, I tried doing everything when VNC'ed to the RPi. Same results. Cooling is disabled.

Here is a Verbose log with INDI, Capture and Camera Driver checked.

Comparing the log with mine, they seem to match until I get to the following.
Yours:

[2024-04-07T11:21:43.851 MDT DEBG ][ org.kde.kstars.indi] - ZWO CCD ASI2600MM Pro : "[DEBUG] CCD ID: 1 Width: 6248 Height: 4176 Binning: 1x1 Image Type: 0 "
[2024-04-07T11:21:43.856 MDT INFO ][ org.kde.kstars.indi] - ZWO CCD ASI2600MM Pro : "[INFO] The CCD Temperature is 0.000. "
[2024-04-07T11:21:43.856 MDT DEBG ][ org.kde.kstars.indi] - ZWO CCD ASI2600MM Pro : "[DEBUG] setupParams ASISetROIFormat (6248x4176, bin 1, type 0) "
[2024-04-07T11:21:43.856 MDT DEBG ][ org.kde.kstars.indi] - ZWO CCD ASI2600MM Pro : "[DEBUG] Pixel format 0 is supported by SER recorder. "
[2024-04-07T11:21:43.856 MDT DEBG ][ org.kde.kstars.indi] - ZWO CCD ASI2600MM Pro : "[DEBUG] Pixel format 0 is supported by RAW encoder. "
[2024-04-07T11:21:43.856 MDT DEBG ][ org.kde.kstars.indi] - < ZWO CCD ASI2600MM Pro >: < CCD_CONTROLS >
[2024-04-07T11:21:43.861 MDT DEBG ][ org.kde.kstars.indi] - < ZWO CCD ASI2600MM Pro >: < CCD_CONTROLS_MODE >
[2024-04-07T11:21:43.861 MDT DEBG ][ org.kde.kstars.indi] - < ZWO CCD ASI2600MM Pro >: < FLIP >
[2024-04-07T11:21:43.862 MDT DEBG ][ org.kde.kstars.indi] - < ZWO CCD ASI2600MM Pro >: < CCD_VIDEO_FORMAT >
[2024-04-07T11:21:43.863 MDT DEBG ][ org.kde.kstars.indi] - ZWO CCD ASI2600MM Pro : "[DEBUG] Frame ROI x:0 y:0 w:6248 h:4176 "

Mine:
[2024-04-08T12:55:10.520 EDT INFO ][ org.kde.kstars.indi] - ZWO CCD ASI2600MM Pro : "[INFO] The CCD Temperature is 0.000. "
[2024-04-08T12:55:10.520 EDT DEBG ][ org.kde.kstars.indi] - ZWO CCD ASI2600MM Pro : "[DEBUG] setupParams ASISetROIFormat (6248x4176, bin 1, type 0) "
[2024-04-08T12:55:10.520 EDT DEBG ][ org.kde.kstars.indi] - < ZWO CCD ASI2600MM Pro >: < CCD_COOLER_POWER >
[2024-04-08T12:55:10.520 EDT DEBG ][ org.kde.kstars.indi] - < ZWO CCD ASI2600MM Pro >: < CCD_COOLER >
[2024-04-08T12:55:10.521 EDT DEBG ][ org.kde.kstars.indi] - < ZWO CCD ASI2600MM Pro >: < CCD_CONTROLS >
[2024-04-08T12:55:10.524 EDT DEBG ][ org.kde.kstars.indi] - < ZWO CCD ASI2600MM Pro >: < CCD_CONTROLS_MODE >
[2024-04-08T12:55:10.524 EDT DEBG ][ org.kde.kstars.indi] - < ZWO CCD ASI2600MM Pro >: < FLIP >
[2024-04-08T12:55:10.524 EDT DEBG ][ org.kde.kstars.indi] - < ZWO CCD ASI2600MM Pro >: < CCD_VIDEO_FORMAT >
[2024-04-08T12:55:10.525 EDT DEBG ][ org.kde.kstars.indi] - ZWO CCD ASI2600MM Pro : "[DEBUG] Frame ROI x:0 y:0 w:6248 h:4176 "
[2024-04-08T12:55:10.529 EDT DEBG ][ org.kde.kstars.indi] - INDI Server: "2024-04-08T16:55:10: Client 27: new arrival from 127.0.0.1:60650 - welcome!"
[2024-04-08T12:55:10.529 EDT DEBG ][ org.kde.kstars.indi] - INDI Server: ""

Your log does not contain CCD_COOLER or CCD_COOLER_POWER attributes.
I don't know how to explain their absence. There is the ~/.indi ASI2600mm file you might see if anything in there looks out of place.

I’m not sure what the problem actually was, but Jasem said this morning he recompiled all the drivers and pushed them to the update site. I updated my RPi with the latest and everything is working again. Yay!