I realize you got it working but have you considered LTE interference?
Somewhere I commented that I have to re-align my antennas a couple times a year as seasons change and that for me at least, I was fairly certain it was just a coincidence that it aligned with this firmware this round.
Well, I finally got around to my seasonal adjustment last weekend and unfortunately it did not correct all of my issues. I still had ONE channel that was unwatchable...
I found a thread here about possible LTE interference and decided to try one of the recommended filters.
Not sure if it helped enough to keep me from having to realign a few items a year but I am really optimistic about it.
I know the larger antenna fixed your issue but maybe something to consider, especially if it comes back later.
As a bonus, not only did the filter fix my one troubled station but I picked up two new ones!