Usually if we have some changes in source VDB, after we update the source model in designer, we will see the changes.
But for procedure, if we add a new procedure in source VDB, after update SM, we only can see the procedure, but can't see the paramenters of that procedure. We have to manually add them.
In this way, in the future, every time when we update our SM, our procedures parameters will be gone, we have to add them manually.
According to Ramesh – "That sounds like Designer bug to me. You should log a JIRA with Teiid Designer."