It seems that it is impossible to link listens with the same MSID to different recordings.  This is consistent with my reading of the API docs.

This is not a particularly obscure edge case. Such a collision is likely enough for the music I listen to that I wonder how many of my manual links have been in vain. Discourse user biocv reported similar issues in other genres.

Here is a concrete example: tracks https://beta.musicbrainz.org/recording/d57d7065-020f-4648-b1ca-12c9ba72f78d and https://beta.musicbrainz.org/recording/21c4d8d7-bd52-47f1-b0df-4a6c337a8749 are distinct recordings of the same work by the same artist, 25 years apart.  They even appear on the same release.  They do have different lengths.

I scrobbled them and attempted to link the resulting listens to their respective recordings.  Here are the results, copied from listenbrainz.org.

{
  "inserted_at": 1718243312,
  "listened_at": 1718243256,
  "recording_msid": "2c25eea7-be55-492e-b81a-3f2e925eae61",
  "track_metadata": {
    "additional_info":

{       "duration_ms": 113063,       "media_player": "io.github.zyrouge.symphony",       "recording_msid": "2c25eea7-be55-492e-b81a-3f2e925eae61",       "submission_client": "ListenBrainz Android",       "submission_client_version": "2.6.1"     }

,
    "artist_name": "Johann Sebastian Bach",
    "mbid_mapping": {
      "artist_mbids": [
        "7002bf88-1269-4965-a772-4ba1e7a91eaa"
      ],
      "artists": [
       

{           "artist_credit_name": "Glenn Gould",           "artist_mbid": "7002bf88-1269-4965-a772-4ba1e7a91eaa",           "join_phrase": ""         }

      ],
      "caa_id": 31587516986,
      "caa_release_mbid": "fed9286f-4145-4fe7-b130-36744a6bdd00",
      "recording_mbid": "21c4d8d7-bd52-47f1-b0df-4a6c337a8749",
      "recording_name": "Aria aus den Goldberg-Variationen",
      "release_mbid": "b304abb5-c039-494f-bc50-37490aca74c5"
    },
    "release_name": "A State of Wonder: The Complete Goldberg Variations 1955 & 1981",
    "track_name": "Goldberg Variations, BWV 988: Aria"
  },
  "user_name": "VBZPPlNQyJ"
}

and

{
  "inserted_at": 1718245462,
  "listened_at": 1718245369,
  "recording_msid": "2c25eea7-be55-492e-b81a-3f2e925eae61",
  "track_metadata": {
    "additional_info":

{       "duration_ms": 185475,       "media_player": "io.github.zyrouge.symphony",       "recording_msid": "2c25eea7-be55-492e-b81a-3f2e925eae61",       "submission_client": "ListenBrainz Android",       "submission_client_version": "2.6.1"     }

,
    "artist_name": "Johann Sebastian Bach",
    "mbid_mapping": {
      "artist_mbids": [
        "7002bf88-1269-4965-a772-4ba1e7a91eaa"
      ],
      "artists": [
       

{           "artist_credit_name": "Glenn Gould",           "artist_mbid": "7002bf88-1269-4965-a772-4ba1e7a91eaa",           "join_phrase": ""         }

      ],
      "caa_id": 31587516986,
      "caa_release_mbid": "fed9286f-4145-4fe7-b130-36744a6bdd00",
      "recording_mbid": "21c4d8d7-bd52-47f1-b0df-4a6c337a8749",
      "recording_name": "Aria aus den Goldberg-Variationen",
      "release_mbid": "b304abb5-c039-494f-bc50-37490aca74c5"
    },
    "release_name": "A State of Wonder: The Complete Goldberg Variations 1955 & 1981",
    "track_name": "Goldberg Variations, BWV 988: Aria"
  },
  "user_name": "VBZPPlNQyJ"
}

 

Note that both are linked to recording MBID 21c4d8d7-bd52-47f1-b0df-4a6c337a8749, even though I tried to link them to different recordings.