Error 1304 when creating a procedure after a drop if exists
Is every client's updateProc100 identical?  Or is that proc generated by code had has code specific to the client?

If it is identical to all clients, suggest creating, but not dropping, a single copy of it in some 'common' DATABASE.  Then only do

 CALL common.updateProc100();


If there is something tailored to each client, could it be an argument?  And then do prepare+execute to build and run the specific stuff?

Back to what you currently have...


Procs are specific to a DATABASE.
Is each client specific to that database?  That is, are you sure there was a USE (or equivalent) before doing the drop+create+call+drop?
What happens at "intervals after" the login?
Can a client be logged in from two places?
Does the Procedure have an interlock so that it cannot be executed twice?
What is the current mechanism for saying "client 'X' has already called 'proc100'"?