Hello! I've built a network dataset using GTFS data - in both Pro and Desktop - and in neither case will the dataset use any transit options. It will walk the whole way for all analyses. In Desktop, I've inspected the various elements - transit lines, stops, connectors, streets - and everything is connected. If I run the analysis without excluding the transit lines and connectors from the final polygons, the polygons will extend along those.
It seems like the GTFS file is missing the "calendars" file, but the guide provided for Pro says that is OK, as long as "calendar exceptions" is there and I run the analysis for a specific date within the provided date range.
The Pro geodatabase is too big to attach here, so I've uploaded it to DropBox, in case you want to take a look. Thank you very much for any help!