Ho Hum.
Maybe I got it wrong, but that was my understanding of things when I did a bit of work on A/P installation and certification about 35 years ago.
Thinking about it if you wind on Aileron trim, or burn to a fuel imbalance, with the A/P engaged, then when you disengage, the aircraft will roll.
I think perhaps the bit about being in trim may just apply to Approach and Land modes, so you don't get any surprises near the ground.