There are different rules for translators depending how it got licensed. Any translator that was applied for in the 2017 filing window for AMs is permanently tied to that station. That's why the 99.9 cannot rebroadcast any other station ever.
Those that were part of the 2015/16 250+ waiver window must rebroadcast the AM for 4 years. Any others can be changed.
Where does WMVX's 98.9 Translator fit into that scenario?
(As far as I can tell, it's not rebroadcasting ANY AM.)