Yea I think you have to let that through. I had a situation similar to that a few weeks ago as commish and did the same thing. It’s not like one guy sent a “joke trade” and it immediately got accepted (happened last year where some dingleberry jokingly sent David Johnson for RGIII and was going to take it back immediately but the other end was on his computer and saw the trade an accepted it). This was an equitable trade, especially knowing what we knew before the games started. Tough luck for not remembering to cancel.