I have a multi-tenant view implementation that uses a RADIUS based 2FA and custom UPN suffixes for each tenant. If logging in with the old style DOMAIN\SAMAccountName, authentication is instant and the user is passed through to their VDI pool without issue. If logging in with the custom UPN suffix (user@mycompany.com) the 2FA authentication is instant (verified with the 2FA provider and logging), but there is about a 45 second delay before the user is authenticated against view and passed through to the pool.
I've read several posts that reference a general issue with custom UPN suffixes, and am looking for direction to try to sort the issue out or a workaround for the time being (that will still use the custom UPN suffix)
TIA