@infO_Overlord Different instances of #Mastodon and #GnuSocial have different subsets of the same conversation. This is by design of the federated network...
This is exactly why e.g. I simultaneously use several @AndStatus accounts at different instances. #AndStatus application helps me see copies of the same messages at different instances, choose as what user/at which instance I want/can take part in the discussion, collapse duplicates visually in a timeline.