When interpreting changesets from TFVC, the TFS plugin will attempt to map domain accounts (i.e. DOMAIN\alias) to Jenkins accounts.

The default mapping strategy (Resolve user using 'DOMAIN\alias') is to provide the string (received from TFVC) as-is to Jenkins, which causes Jenkins to convert the username from DOMAIN\alias to DOMAIN_alias. If your Jenkins users are named with a different convention, try another user mapping strategy.