What has happened is that one of the Replica's exported their data changes with the option "Switch Roles", but then those data changes were not imported (yet) by the relative replica. This is ok.
Let's say we start with the replica's in the following roles: GDB 1 = Sender GDB 2 = Receiver.
GDB1 exports dc's with the option to "Swith Roles". So the roles at the END of the export are: GDB 1 = Receiver GDB 2 = Receiver
==== THIS IS YOUR CASE - both replicas are RECEIVERS, this is OK ======
When GDB 2 imports the dc's - then it will switch roles and become a SENDER. So, after importing dc's GDB 1 = Receiver GDB 2 = Sender
So - to fix your case 1) If you have the latest DC message, simply import it to the appropriate replica 2) If you do not have the DC message - it can be recreate using the "Re-Export Unacknowledged Changes" command/gptool (note: different from the Export Data changes message" command)
If you are unsure of which replica geodatabase needs to do the re-exporting, an easy way to do it, is to simply open the Re-Export Unacknowledged messages command in Catalog. The tool will filter all but those replica's that are able to re-export. Only one of the gdb's will qualify.