Shoot me a diagnostic if you can catch this again! Invalid signal levels should automatically be filtered out.
Yeah, B66 and B71 are natively reported wrong on many devices due to an Android bug. SignalCheck tries to catch these and report them as B66/B71, but it's tricky because in some instances the incorrect band is actually a possible valid result. I'm not aware of B7 showing up, if someone catches that please send a diagnostic.. it is likely B66/B71 being reported incorrectly but not getting caught.
The report you sent showed the app was displaying B2 and the icon at the time was also B2--I checked the graphics to make sure the B2 icon didn't actually say B71, LOL.. if it happens again send another report! I don't recall any recent reports of the notification icon falling out of sync with the app itself.
Your G4 is running Android 6.0, which does not report EARFCN info. SignalCheck is displaying it as band 41 because PLMN ID 311490 is leading it to believe that it is a former Clear site, so it defaults to B41 unless another band is identified another way. With 311490 now being used during the merger transition, it's throwing things off. Unfortunately the app isn't going to be able to know if it's a Clear site or a merger-related thing.. perhaps I'll just remove the default band for now, since newer devices will be able to figure it out anyway. These multiple PLMNs are going to be even more problematic than they were before, because they aren't being used the same way in every market.