"The [user.mobilePhone] property must be a valid phone number that can be parsed to a E.164 formatted value" error

[mcsymiv]

Hello,

When submitting text value, e.g. "my phone", to 'user.mobilePhone' to /api/user/registration, we receive E.164 error, which is expected.

But, I can perfectly create users with following values '123text', 123z'

And, mobilePhone values like '12z', 12zzzz', yield expected error message - Invalid number

What are exact formatting rules for user Mobile phone [user.mobilePhone] field? Is this a bug, or FA allows some other phone formats which are not described in the documentation? (https://fusionauth.io/docs/apis/users)