The Fulcrum wheel with the cassette required a Di2 adjustment, as the guy at the bike shop said it didn’t need a washer under the cassette.
… so now when I shift to the big cog in back, everything works fine, the RD moves over, the chain shifts, the pulley is lined up perfectly on the cassette…. then 3 seconds or so later, Di2 decides to trim or something and moves the pulley back towards the little cogs about 1/3 the way to the next cog, but enough to make the chain jump back into the next smaller cog without any buttons being pushed.
Can I just reset the whole thing or what do I do?
It’s an original Di2, don’t know the #, first series I believe.