Namespaced claim replaces period (.) with colon (:)

I’m using a rule to include a custom namespaced claim (e.g. in the idToken, per the guidelines here: Create Namespaced Custom Claims. This works great; when I test out my login flow I see "": "value" in the resulting profile data.

However, I’m trying to connect to this first Auth0 tenant from another tenant, using an enterprise OIDC connection. When I do so, it looks like Auth0 renames my custom claim to https://example:com/claim in the resulting user profile (replaces the dot/period with a colon). Why does this happen? I spent several hours debugging my setup only to realize that Auth0 was replacing that character, and I have not been able to find any documentation warning about this. https://example:com/claim is not a valid URI.

I wonder if this has something to do with why properties with . characters are not allowed in app_metadata or user_metadata? Could that restriction be relaxed? Property names that include . are very likely if you follow the recommendations of using a domain name as a namespace.