Star Trek: Stargazer
Ralic and his forces ambushed the Stargazer. During the battle, one of the attacking shuttles dropped its shields just long enough to allow Surok to transport aboard, disable the crew and commandeer the vessel.
The Romulan shuttle, complete with cloaking device, was renamed Avalon. No mention of this vehicle was made in the log nor passed up the chain of command.
Avalon was lost while Surok and Captain Dorgo were aboard. After a catastrophic failure of the teleporter pad, which removed the aft of the shuttle, Surok was able to pilot the failing shuttle back close enough to Stargazer to allow Lt. Baristani to transport the crew members onto her shuttle.