Monthly interval schedule results in a flow run every 30 days

[bkkkk]

Bug summary

When setting a new Interval schedule for a deployment, you can provide an interval of P1M with a given anchor date. I would expect runs to be scheduled 1 month apart from the anchor date. However in the UI this is actually presented as "Every 30 days" and flows are scheduled at 30 day intervals from the anchor date.

For example with an anchor date of 2024-01-01 10:00, I would expect the next run to be on 2024-02-01 10:00, 2024-03-01 10:00, and so on.

Instead it's more like 2024-01-31 10:00, 2024-02-30 10:00, and so on.

Version info

Version:             3.1.0
API version:         0.8.4
Python version:      3.11.11
Git commit:          a83ba39b
Built:               Thu, Oct 31, 2024 12:43 PM
OS/Arch:             darwin/arm64
Profile:             local
Server type:         server
Pydantic version:    2.10.2
Integrations:
  prefect-slack:     0.3.0
  prefect-aws:       0.5.2

Additional context

No response