@SeanSmith111 some more info from the geocoding team...
The best practice recommendation is to combine the four datasets into one prior to building the locator and then building a single POI locator.
This is documented here: Combine multiple data layers into a single locator—ArcGIS Pro | Documentation
And here's a tutorial: Tutorial: Create a locator with more than one dataset of the same role—ArcGIS Pro | Documentation
Doing this will ensure optimal quality of suggestions/results and performance.
Having said that, what you've encountered here is unexpected and we'll investigate further internally - potentially there's a bug lurking in this issue somewhere.
It would still be great to know the answer to this question if you have time:
Question: are you able to open the mmpk in ArcGIS Pro, specify/use the locator within the mmpk, and still get suggestions?