Once again it was just one pin on 81161 that caused this. It wasn't soldered properly, because I really should use solder in paste or at least clean the old solder and not just reflow the solder that was there. I'm still learning hot air soldering. But anyway after making sure that every pin is soldered correctly that suspicious resistor has now 8K - which is I guess good. At least close enough to 7.8K-7.7K of other resistors.From what I found, 81161 is decreasing resistance of this resistor (without it resistance is 10K, just like after desoldering this resistor from the board). But on this phase even with a 81161 from the other phase it still has that 8.7K resistance.