I would not assume that the insulin lost efficacy. Every time I have thought that and changed the pen, I've found it's not the insulin, but the dose having gone stale and Bandit needing more insulin. I would stay with 1.25U. Maybe the dive from 143 to 69 on 8/8 triggered a bounce that took longer to clear (especially if the dose was not a good one). Today's AM was the 6th cycle from that cycle and some cats go high before they break a bounce. Maybe that's what she was doing today.