You may have gotten that answer but you didn't get it from me (unless I was trippin' at the time... but I don't do that.)
Yes, because SMB (any version) is a TCP-based protocol as opposed to UDP based, Access IS sensitive to network drops. Switching to SMB 2 and later to SMB 3 simply means the session can more easily buffer packets and optimize its use of allocated memory resources. A feature of most protocols is the ability for the original sender to retry after a time-out. There can be a retry limit. In the final analysis, either the session layer keeps on going or the entire virtual connection collapses.
While the exact reason depends on whatever the network gurus said it was and I didn't see that particular dispatch, I would say that it is a VERY HIGHLY LIKELY reason for the "login when reconnecting" requirement. The details of any protocol would be "ordained" by the IETF (Internet Engineering Task Force) and/or IEEE (Institute of Electrical and Electronics Engineers). If you looked up IETF + ODBC, you might get a reference to RFC 2371, the current standard for database transactions under the title "Internet Transaction Protocol". However, as it turns out, ODBC is actually just an API that embodies an implementation of ITP. There is no RFC document for ODBC.