Right, so certain fields types do not natively Sync across in their original field types and default back to a "text" equivalent.
For example a User field and a List User fields definitely come across as text.
For a User fields it's easy to create a new field of type Formula user with a formula of
ToUser ([user Sync field])
But for the list user, the formula is more complicated.
Here is a tested example of a formula that works and can be extended to up to as many as you will likely have or else right up to the maximum which I think is 20 userids.
var text StripOutSquareBrackets = NotRight(NotLeft([userlist],1),1);
var user UserOne= ToUser(Trim(Part($StripOutSquareBrackets,1,",")));
var user UserTwo = ToUser(Trim(Part($StripOutSquareBrackets,2,",")));
etc...
var user UserTwenty =
ToUser(Trim(Part($StripOutSquareBrackets,20,",")));
ToUserList($UserOne, $UserTwo, etc, $UserTwenty )
