No

Does it happen every time? I don't see a note where it indicates that all workstations need to be re-installed.

The 1099 hotfix didn't cause this, the PU did.  It's quite common for PU's to require re-running WSSETUP on all clients.

Thanks.

The Release Notes that state that workstation setup must be re-run are in a prior product update.  If the last prior update had already been installed, you would not have needed to re-run wssetup after installing this one. Remember that product updates are cumulative, so when installing one, it is best to check the release notes of all of the pu's since the last one installed. 

Thank you Jim. Good idea.