After December 15, 2024, we set new API tokens to expire in one year by default. When you create an API token, you can set the expiration date to be from one day up to one year.
After March 13, 2025, we set API tokens you created before December 15, 2024 to expire in one year. These API tokens will expire between March 14 and May 12, 2026.
So, you didn’t set an explicit expiration date but Atlassian expired it anyway. This has the best explanation by timing: your post coincides with this window.
In addition to token expirations, API Tokens can now have scopes and when using those tokens, the URL is different. It looks more like: