Encrypted files cannot be merged. There is no sensible way to combine two versions of ciphertext, and a tool that tried would silently lose one of them. So writes use compare-and-swap: your client says "update this secret, and only if it is still at version 7". If someone beat you to it, your write is rejected.
The client then refetches, verifies the new state, re-applies what you asked for, and retries a handful of times with a short backoff. You will normally not notice. If it genuinely cannot settle, it stops, reports failure, and tells you the current state. It will never force its way through, and it will never auto-merge.