Same movie in two places?

@Peter-pbn: If the movie was first and it was later broadcast as part of a series it should be added to the series as a shell episode: https://help.imdb.com/article/contribution/titles/episode-guidelines/GDF7HR6CCCBKU3CP?ref_=helpsrall# This very strongly suggests the review should be added to the movie and not the episode.

The guideline doesn't say anything about reviews. If you watch it as part of the series it makes sense to post the review there. The episode may also in some cases be edited in a specific way or contain additional material.

@Peter_pbn: I see your point about watching something as part of a series. That being said, I could understand it if IMDb wouldn't want user reviews listed for "proper" shell episodes (episodes that are the same as the movie, no editing or adding of material) as IMDb wants all the information on one page, the one for the "proper" title. In that case, customers wouldn't need to check both titles to have all the information IMDb has to offer. But you're right; it is not explicitly stated either way. (I don't know if this particular title is a "proper" shell episode. If not, it would make sense to me to add the user review to the episode and not the movie if that is what the OP watched.)