If Hellcat is owned by the server, there is no animation to getting in pilot or copilot for the first time. The transfer is instantaneous. Subsequent getting in and out works correctly.
This does not happen if the Hellcat owned by the player's client or if this is tried in editor. This is dedicated server issue.
Spawn 2 Hellcats "I_Heli_light_03_F" on the fly, one on the server and one on the client.
Go to server spawned one and select action get in pilot seat. Player instantly appears in pilot seat. To exit player goes through lengthy animation. Trying to get in again plays long animation now.
Go to client spawned Hellcat. Everything works correctly.