For whatever reason, they don't appear to actually be using minute markers when the Wayfinder face style is set to minutes instead of hours on the dial.
For example, there are five tall marks between 00 and 05 when the face style is set to minutes. If these were really representing minutes on the hour (or seconds on the minute), there should only be four tall marks here (for example, 1, 2, 3, 4 between 00 and 05).
I think what they're really showing here in the minutes style — rather counterintuitively — is degree markers. If you tap the dial and switch it to the compass, you'll see the same marker setup: five tall marks between each of the 12 listed degree divisions. For example, five markers between 0 degrees North and 30 degrees, which is correct — markers for 5, 15, 20, 25 degrees.
When the face style is set to hours, there are 9 alternating short and tall marks between 12 and 1, and those represent half-minutes and full minutes (or half-seconds and full seconds).
TL;DR, if you want to be more easily able to tell what the precise minute on the hour is, use the "hour" face style rather than "minute".
I don't know enough about navigation conventions to be able to tell if the way Apple has set up the "minute" style is correct or not, but as a layman it definitely seems weird.