Yes, think you're right on that one. How strange. I have been doing weekly commutes TXL-FRA on LH for about three years now and it always appeared to me that the mid-day AUH flight and the evening one were gating up at A0/A1 whenever I walked past there on the way to/from the bus stops.

But you are right about it now seeming to be C departure (just checked on TXL site and C88 is indeed the departure gate for all flights this week.

Bad luck OP - it's Terminal C for you again, although there is a new AB lounge there!