Affects at least the internal-v2020.02 tag.
Steps to reproduce:
- Log in, and make sure not to reload the page
- Upload an artifact and enter the deployment window
- Once you get to the Phased Rollout dropdown, check if it can be selected
Result: The dropdown is disabled, and only the 100% rollout option can be selected
It seems that one can work around the bug by reloading the page. As long as one remains logged in, the phased rollout option is available.