I have the same problem. I have a formula on 14 folders, but i cannot add it to new ones. This is what I got from support, they make it seem like it's a "feature":

When creating a Formula Custom Field in ClickUp, you can only assign it to a single location (such as a specific list, folder, or space). If you want to use the same formula in other folders, you’ll need to manually recreate it in each location. This restriction does not apply to other custom field types like text, number, or dropdown fields, which can be reused across multiple locations.

Why This Limitation Exists:

• Field Dependencies: Formula fields often reference other custom fields that may not exist or may differ in other folders or lists. Limiting formulas to one location ensures all referenced fields are present and consistent.

• Data Integrity: Restricting formulas to a single location helps maintain accurate and reliable calculations.

• Performance: Allowing formulas across multiple locations would require additional validation and could impact performance.

• Customization: Each folder or list may have unique data structures, so formulas are kept local to ensure they work as intended.

-----

What I think: this feature was a little bit buggy, somebody found it, checked that it's difficult to fix, noticed the majority of the users don't use it -> remove it to prevent disasters. That's very logical do, but keep in mind that whoever was using this feature is a power user. Give us that feature back 🙏