Originally Posted by
AnkleWork
You should be able to up-shift a couple of gears in back while dropping a gear in front and thus avoid cross chaining even while climbing.
Yes, you SHOULD be able to do all sorts of things, including ride cross chained if you choose to. There may be technical reasons why it's good to avoid cross chaining, but that's not the same as not being able to.
In any case, the OP isn't asking whether it's desireable to ride cross chained, he's asking why his bike drops the chain to the inner ring when it does, and how to solve it. The fact is that Di2 bikes generally can handle cross chaining and his can't so there must be a reason.