In release R2022a we added the argument TieBreaker (which can be used case insensitively) to control how ties are broken in round. Are you using an older release?
x = [3.5, -3.5];
round(x, Tiebreaker = "plusinf")
round(x, Tiebreaker = "tozero")
round(x, Tiebreaker = "fromzero") % default
You can use this with the N input argument too.
round(1.25, 1) % Remember "fromzero" is the default
round(1.25, 1, Tiebreaker = "tozero")
