When using database cache on an Percona XtraDB cluster Truncate's are quite blocking. This means all requests for the cache will wait for the tabel to finish.
When a SST (an initial sync to a new node) is running this can result in waiting for a lock indefinitely which means the sync will fail and the cluster will go down. Other than changing the caching backend to another service, we think not allowing TRUNCATE will aliviate the issues at least. Then we can at least be sure deploying multiple Drupal sites will not result in unfortunate issues where you run into a deadlock situation.
Not too sure what the proper way to fix this would be, but i think removing the possibility for TRUNCATE is at least a start.