Problem: The tokenized Unwatch link in the PR email footer removes the recipient as a watcher on a single HTTP GET. Enterprise email gateways (Microsoft Defender Safe Links, Proofpoint URL Defense, Mimecast and others) automatically follow links in inbound mail to check them. This triggers the Unwatch action without the user knowing, so users silently stop getting PR notifications and PRs drop off their "I am watching" filter.

Suggested solution: Make the GET request to the Unwatch URL show a confirmation page only. Remove the watcher only after an explicit, separate state-changing request (for example, a POST when the user clicks Confirm).

Workaround: Ask the email-security team to exclude Bitbucket Unwatch URLs from link pre-fetching. Affected users can manually re-watch the PR.