@Marvin I used to be able to do custom run like this by providing a list of strings. Now it's showing this error in UI. What's changed?

It seems there have been several updates and bug fixes in the recent Prefect releases, but nothing directly related to handling lists of strings for custom runs was highlighted in the latest release notes or documentation excerpts. However, there could be changes in how Prefect 3.x handles specific configurations or parameters that might affect your use case. Given your situation, I'd recommend checking the specific error message you're encountering and verifying your configuration against the Prefect 3.x upgrade guide to ensure compatibility. Additionally, reviewing any recent changes in your setup or Prefect version might help pinpoint the issue. If you have more details about the error message or the specific context, feel free to share, and I can help investigate further.