First, keep in mind that the email you're describing will only be sent upon Completion of the Envelope -- so if there are other recipients after the In-Person signer in the routing order for the Envelope, the In-Person signer wouldn't receive the email until all recipients have completed their required actions and the Envelope is complete.
Second, you might want to verify (in Preferences >> Features within the DocuSign web console) that these two settings are set as shown here:
These settings control whether or not emails are sent to "embedded/captive" recipients. Even though you're using "In-Person" signing -- it sounds like you're launching the host's signing session using "Embedded Signing" (i.e., RequestRecipientToken), so these settings might be affecting whether or not the email actually gets sent to the signer.