AnotherGCApplic(AGA) changed jobs before approval
actually, a couple of weeks before an RFE. AGA sent in the employment letter from the new employer, one paycheck from the new and one from the old, and got approved in 3 business days after receipt of RFE.
You can lookup more posts by AGA for more details.
You lawyer is correct, AGA thinks - just that most advise you to wait for an RFE before informing of the job change - in AGA's case, AGA did not even have the time to inform BCIS before the RFE. That is pretty much the only decision you might have to make.
Just make sure, though, that the job responsibility listed in the letter is same/similar to the old one in the LC (even if responding to RFE or informing them about AC21).
hope this helps.