Well, this is a bit weird. I'll try to describe, but might have to resort to creating a log.
I have a NXDN trunk system on UHF and a MotoTrbo system on 900 that seem to be interacting somehow.
This is on a 536HP with both upgrades.
When scanning the NXDN system and finding the control channel, all works as it should. The scanner then moves to the MotoTrbo system and shows the control channel for the last NXDN site. The continues as the scanner moves from site to site on the MotoTrbo system.
If I hold on a site on the MotoTrbo system then scroll to another site, the system behaves normally. When I release the Site Hold, the scanner reverts to the odd behavior on the next pass of the MotoTrbo system.
I uploaded the MotoTrbo and NXDN systems into ARC536. The only oddity I found in either is that I had somehow forgot to put the Color Code in for two sites on the MotoTrbo system. Both sites were set to Search. I corrected that by putting in the correct CC and loading both systems back on to the SD Card.
Once reinstalled in my truck, the scanner seemed to work normally. I did the same with my 436HP, but since that scanner doesn't display the control channel frequency, I don't know if it's corrected. I don know that I'm not seeing "CON" on any of the sites. Since I'm about three air miles from one site and can receive it on my SDR set up, I know the frequency is right.
I have a different MotoTrbo system that has all of the Color Codes programmed correctly and that works fine. I wonder if it's somehow related to the Color Code search?
Again, a weird issue. Has anyone else seen anything like that?
ETA: I might have stumbled on the answer. I was looking at the settngs on the MotoTrbo system and discovered that the digital threshold had somehow changed to MANUAL and 0. ARC536 allows Manual settings down to 0, even though Sentinel doesn't. I looked at that same system in Sentinel and found that the settings were correct. Hmmmm. I last loaded that system using ARC536, but I don't have any idea of how that setting changed. I wrote the system back into the scanner with the correct settings and at least on my 436HP it seems to be working better. I'm seeing "CON" on the two closest sites to me, which is about how it should work.
More reloading and testing on the mobile in the morning.