Obviously, somebody has already fixed remaining errors, so the validation page is "green" now :)
 https://wiki.openstreetmap.org/wiki/Relation:route#Members, states "The order of the members [with the 'stop' role] in the relation should be identical to the order in the timetable".

If a mapper changes a route relation and doesn't care about stops order, stop_positions are often added to the end of the route relation member list, which is incorrect.

For other answers please see metro mapping guide: https://wiki.openstreetmap.org/wiki/Metro_Mapping

Best regards,
Alexey