The log

fmt.Sprintf( "Unexpected tx response from proxy during recheck\nExpected %X, got %X", r.CheckTx.Data, memTx.tx, )

is not correct, the expected is the Response while the got is Request which makes the comparison confusing.

I think it can be changed to

fmt.Sprintf( "Unexpected tx response from proxy during recheck\nExpected %X, got %X", req.GetCheckTx().Tx, memTx.tx, )