Oh, I think I understand what was changed. It seems like the previous change here was an addition of a way specifically for the FastTrak lane. It seems like https://wiki.openstreetmap.org/wiki/Lanes provides the most relevant reason to map this as a separate way, when an HOV lane is concerned:

"If one or more lanes of the road are restricted to high-occupancy vehicles (typically vehicles with 2+ occupants, although this varies by jurisdiction). Most useful if entrance/egress is permitted at any point along the route; if entering or exiting the HOV lane(s) is only permitted at certain locations, modeling the HOV lane(s) as separate ways is preferable."

However, OsmAnd still tells drivers to "turn right onto Exit 12A", the exit onto Mission Boulevard, rather than continuing along I-880 when the route actually continues along the freeway. I suspect that the reason is due to this fork in the road, causing OsmAnd to identify the regular, right-side lanes of 880 as "Exit 12A".