yes, that's a problem. These two hacks don't work together properly. It's because the viewingpermissions are just read out from the db when the cache is updated, but it won't if the script reads from the cache. That is one of the queries which are reduced when reading from cache
i don't know the hack of latest XX but maybe, you can add the threadinfo into the cache also, so it should be working
as said, i can't code such workarounds for other hacks whil beta-phase but maybe i find a way after the full release