I have a very large project file in ArcGIS pro that is highly customized, so creating a mobile map package from our Enterprise Portal is not an option. I am using the Create Mobile Map Package tool with different areas of interest for our different corporate divisions and uploading the resulting .mmpks to our portal. The maps are downloadable on Field Maps and everything seems to be working except related record filtering.
When I leave the "Keep only the rows which are related to features within the extent" checkbox un-checked, the .mmpks' file size is very large (>6m related records split between two tables), but the related records do appear in the mmpk via Pro and Field Maps. When I export a mmpk with that box checked, however, only about 10% of the related records appear where expected. For example, there should be ~400 related records for a set of features within the extent (like there are in the my Pro project file) but in the mmpk, there are only 9.
What am I missing here?