Thanks @Andreas_Hegenberg! Retested on 6.974 (build 2026102208), and this now works with my existing configuration.
'Select Template Window' opens at X=0, Y=0, Width=1268, Height=940, matching the saved action values. I also cancelled and reopened it, and confirmed the same initial geometry.
Screenshot:
One additional little bug I noticed, if you click the 'Select Template Window' button multiple times, it will keep creating new template windows, rather then just capping it at 1 (they all disappear when I press esc still)
The following screenshot shows 3 that I created, and then manually moved to not directly overlap each other to demonstrate it clearer:
Edit: Raised a new dedicated issue for this part for better visibility/tracking:
Will mark this main bug report thread resolved now as the original issue seems fixed.

