Aha, yes, that sounds logical: Servoy loads all the jars in the dirs, regardless their name.
So, in your case, you had basically the old and new Jasper jars there and then either the new or the old one gets used.
Always remove old jars from the plugins (and subdirs), the lib dir and the beans dir…
If you wonder why it works this way when you have to specify the name in the jnlp file anyway: the jnlp file is used to send jars to the Client, when starting a Client. The issue you encountered is a conflict ServerSide, so the jnlp has nothing to do with it.
Glad the issue is solved.
Paul