Yes, this was the problem, you can not send a map as a parameter to a RPC to be executed on the Server (i.e. DropGroup in the last picture- had to change it into a structure that held two arrays). You only get an error in the log. No warnings or errors when compiling the blueprints even though it should realize there is a problem (i.e. it has all the information it needs to determine there will be a problem).
Thank you @PREDALIEN for listening and getting me on track. Pun not intended.