The play count Spotify displays in their application is the aggregated play count for all tracks of the same recording. This means if the same track is on multiple releases, they will all have the same play count.
When recognising the same recording, Spotify takes many factors into account; such as ISRC code, track title, duration and artist name. Even if the ISRC code is not identical, the tracks might still link if the title is the same and the duration is very close.