A family of Microsoft relational database management systems designed for ease of use.
I reported this bug in Build 2604 to the Access team at Microsoft on the 20th. They are looking into it.
In the meantime, rolling back to Build 2603, as has been stated above, will restore the appropriate behavior.
Adding to the complexity, other issues have been identified -- and resolved -- in this Build, so it's unclear where this one stands.
Please note, however, that the data types themselves did not change.
It is a change in the way the data import process recognizes them in the source file. Temporarily rolling back to the prior build will restore the appropriate behavior.
AccessForever.org has articles with advice on Update Bugs.
https://www.accessforever.org/post/how-to-deal-with-update-bugs
https://www.accessforever.org/post/demystifying-microsoft-365-update-channels