When more than two data entries appear in a dedupe query from the same donor, Civi isn’t merging them all and keeping the most recent information as the primary, as it used to, unless the most recent data is on the top right column in the deduper interface.
Additionally, when the most recent data is on the left column, Civi will merge only two entries and remove the rest from the query which defeats the dedupe goal to upkeep our database as the queries aren’t getting fully deduped unless we add manual steps into the process!
Here are some CIDs examples 14407713 - 13248469 - 43448603 - 54708357 that if added to the deduper interface the same way as the pic below, can be used to merge and show what I explained above.

Here are some more CIDs if needed: 43597981 - 3748886 - 55011329 - 59761182.
15266278 - 10813141 - 43452402.
22565353 - 1127553 - 43691017.
22738405 - 11662057 - 41042514.
22918171 - 16866247 - 41064029.
Please feel free to reach out in case my explanation doesn’t make sense! I tried my best but nothing like an actual screen-sharing call to seal the deal :) Ty!