When editing an existing managed event, the UI shows the following error when trying to save changes (e.g., to participant limits only):

“The string did not match the expected pattern”

However, nothing seems wrong with the input. In the backend logs (Docker), the following error appears:

2025-08-06T08:57:53.625091174Z @calcom/web:start: ⨯ [Error: Body exceeded 1mb limit] { statusCode: 413 }

This seems to suggest that the request payload is too large (exceeds 1MB), but the UI does not indicate this – and instead shows a misleading validation error.

Steps to reproduce:

1.	Use the latest version of Cal.com (self-hosted via Docker).
2.	Create a managed event with a description and/or custom configuration.
3.	Edit the event and try changing e.g. only the participant limit or availability.
4.	Click “Save”.
5.	Observe the validation error in the UI.
6.	Check Docker logs → 413 error.

Expected behavior:

If the request body exceeds the limit, the UI should:
• Show a clear error indicating that the payload is too large.
• Optionally highlight which field is too long (e.g., description or JSON field).
• Not show unrelated validation errors like “The string did not match the expected pattern”.

Environment:

•	Cal.com version: latest (as of 2025-08-06)
•	Deployment: Docker (default setup)
•	Browser: Safari
•	Any reverse proxies: haproxy on pfSense