I am running SGP version 4.1.0.771
I was running an LRGB sequence last night and decided I wanted to only use the LUM filter for focusing. So I opened the Control Panel while the sequence was running, went to the Focus tab, selected the SET button under Focus Options - Use auto focus, and checked the Option - Auto focus with filter :Lum: then closed the Auto Focus Option window down by selecting OK, and then closed the Control Panel.
The LUM filter was not used on any subsequent Auto-Focus runs (since I was auto-focusing after 4 frames, and moving to a new filter every frame, the Blue filter was always being used).
I thought in the past that any changes in the Control Panel affected the current sequence, even if the sequence was running.
The log file is here: https://1drv.ms/u/s!AiykFZb1zO59gYdRhOgKofY6EDYv9w?e=Kxoo16
I made the change after I watched an auto-focus run with the Blue filter. Either after 20:49:11.682 or 21:16:28.891
Jerry