Hi,
when value in userinfo JSON response is NULL then in xwiki instead of NULL or empty string, variable name apperar.
Example: if mobilePhone is NULL in JSON, then Phone will be ${oidc.user.mobilePhone._clean}
How to change it to empty string if value is NULL?

in JSON:

See more details regarding the syntax on StringSubstitutor (Apache Commons Text 1.12.0 API) (just added the link to the documentation, thanks for the reminder).
From what I understand It’s possible to provide a default value. In your case I think it should be something like
${oidc.user.mobilePhone._clean:-}
I changed all to:
oidc.user.mapping=birthday=${oidc.user.birthday:-}
oidc.user.mapping=mySite=${oidc.user.mySite:-}
oidc.user.mapping=city=${oidc.user.city:-}
oidc.user.mapping=companyName=${oidc.user.companyName:-}
oidc.user.mapping=country=${oidc.user.country:-}
oidc.user.mapping=department=${oidc.user.department:-}
oidc.user.mapping=displayName=${oidc.user.displayName:-}
oidc.user.mapping=givenName=${oidc.user.givenName:-}
oidc.user.mapping=first_name=${oidc.user.givenName:-}
oidc.user.mapping=id=${oidc.user.id:-}
oidc.user.mapping=mailNickname=${oidc.user.mailNickname:-}
oidc.user.mapping=mobilePhone=${oidc.user.mobilePhone:-}
oidc.user.mapping=officeLocation=${oidc.user.officeLocation:-}
oidc.user.mapping=postalCode=${oidc.user.postalCode:-}
oidc.user.mapping=streetAddress=${oidc.user.streetAddress:-}
oidc.user.mapping=surname=${oidc.user.surname:-}
oidc.user.mapping=name=${oidc.user.givenName:-} ${oidc.user.surname:-} (${oidc.user.mailNickname:-})
oidc.user.mapping=last_name=${oidc.user.surname:-}
oidc.user.mapping=jobTitle=${oidc.user.jobTitle:-}
oidc.user.mapping=mail=${oidc.user.mail:-}
oidc.user.mapping=workAddress=${oidc.user.streetAddress:-}\n${oidc.user.city:-}\n${oidc.user.postalCode:-}\n${oidc.user.country:-}
But now I get everything empyt 
OK, I fixed it by velocity. I added this code to all my fields in Custom Display 
{{velocity}}
#if($value.toString().contains("oidc.user."))
-
#else
$value
#end
{{/velocity}}
but it add <p>
