Batboard

I have 2 questions, the second being the most important.
1.) I feel as if every time I add something or change something in any of my radios, the receive sensitivity gets worse. Does this have any validity to it?
2.) My HT 1250 seems to be having receiver sensitivity issues, sitting here on scan (standard set of 16 conv. channels) it just randomly picks channels and opens squelch for about a half of a second and then goes back to scanning. I can literally nuisance-delete every scan list member from the scan just by sitting here for 5 min with the radio. Also, a more ongoing issue is that when I change channels the RSSI indicator randomly flashes on and off on channels as I'm scrolling through. I fear it may be time for a trip to the dreaded Depot. Help!
Radio is model :AAH25KDF9AA5AN (conv. VHF) with the orange battery contact gasket.
Thanks for your help!

From the tag on the rear of the chassis behind the battery - what is the firmware revision number?

05.03.02

When your HT is breaking squelch, is it in the vicinity of a PC? If it is, and you are using carrier squelch as the only open squelch qualifier on receive, remove the HT antenna to verify that said squelch does not open. If it doesn't, then you have a PC or other device with electronics that's radiating noise that can also cause (#1) that you mentioned. Your firmware is new enough so that it shouldn't cause the problems that you mentioned.

I'll give it a go. I do have most of the channels programmed as carrier squelch as for some reason PL tones don't seem to be consistently placed in radios in this area. (2-way shop inconsistency)
I appreciate your response!