Hi,
Kindly check the default transaction type that is picked while executing ABUMN In it it may be possible that transfer to Asset with Investment measure may not be allowed for posting. In this case better approach is suggested by Ashish Bhatia above, to reverse the AUC and again transfer the cost to IO and in IO mention the correct AUC Asset in the Settlement rule and then settle the cost of IO to the correct AUC and then to the final asset using AIAB and AIBU.
Regards,
Malhar.