Lately I've found both 4-1/28 and 11-1/33 to have lower signal levels than usual, putting them sometimes borderline for reception. Right now I'm getting about a 65% signal level/79% signal quality on 11-1 and 57% signal level/59% signal quality for 4-1. Normally the signal level is closer to the low to mid 90% level. In both cases I do have 100% symbol quality, so the error correction info is sufficient, but the occasional breakup occurs when it isn't, and it's quite annoying.
I'd guess they might be doing some work on the combiner or antenna causing them to run at reduced power levels for some reason, though have no idea if that's really the case. I've been in the process of just switching season passes over to the cable signal version of the channels rather than enduring it anymore.