Me pulling my hair out!
Did you try attenuation by chance while in in a zone and see what that did? Just curious as you'd normally use the attenuation, not squelch in a strong signal area, and it sounds as if the squelch tail may have to do with a fairly strong signal. The channels I had it on were fairly strong to start with but I never did try setting the attenuation on those frequencies...it's worth a try, and you'll miss fewer weaker signals than you would having the squelch up so high.
I didn't try the attenuator. I did what a lot of people were saying to do AFTER their upgrades to see if their settings had somehow changed during that process. Pre-upgrade I NEVER needed to use the attenuator. EVER. Even in an RF rich area like by Midway or O Hare Airports.... The 330 didn't and still doesn't need attenuation. The 396 didn't either. I learned by using my GRE500 that different settings have different effects...so, I decided since it sounded like too much squelch, to play with the settings. So, therefore, I played with settings until 6 made it stop. So, I do the upgrade and it is really a placebo effect in the Chicago area. No improvements that have scientific or measureable improvements. Several people report it has, but it hasn't. I am not sure what they are hearing. But, there are no improvements. It is unfair to peg P25 on the Uniden scanner when I really believe the actual system needs some work. The squelch tail came post upgrade and I don't feel I need to attenuate the Zone I live in when I never had to do that before. It's a negative, not a plus. I upgrade to a firmware that has no improvements but I have a lengthy squelch tail that I either set the squelch to 6 or higher for, or use attenuate. That is just crazy.
Sure, I downloaded a new firmware JUST so I could have an extra step of attenuating a district/Zone I happen to be in at the time where the signal strength is obviously greater in. It is an issue and maybe, just maybe, Uniden will fix it. Maybe they were trying to increase sensitivity....which is great. I like that idea. But, this is a by-product of something from the upgrade. But what?.....
I didn't see anywhere in the upgrade features that the upgrade would "Improve your ability to acquire a lengthy squelch tail and benefit from the standard attenuator feature!" So, I appreciate your suggestion Viper but, I shouldn't have to resort to that when it wasn't there before and the same frequency on the 330 never had it and doesn't at this time. I am not getting on YOUR case. I am just frustrated with work-a-rounds to issues that Uniden may be working....or should be working on at this time. I reported it in the post release thread but no one seemed to care. I will try the ATT tonight when I get home...thanks for the tip. That may help. But, it would be nice if I could go back to the previous firmware. The placebo didn't do much for my 396.