Thank you for sharing your old, large FamilySearch download that you did with RM8 back in 2022 which, according to your recollection, took over 3 days and was incomplete because it maxed out at so many generations. You did a subsequent import to extend it.
I can confirm, as you have already suspected, that the RM database exhibits the duplicate-couples syndrome that we are seeing with RM11 downloads from FamilySearch, in spades. Therefore, we can conclude that every download of an ancestral branch of FamilySearch Family Tree from RM8 to RM11.5 is afflicted with duplicate-couples syndrome if the branch includes parentage involving two relatives of each other.
One couple, at the top of the tree, is duplicated 376 times with the same children who are espoused to each other 189 times. Right, that’s Adam and Eve and RM shows them with 189 or 190 parents each. From a SQLite query:
What this duplication suggests is that between the root person in the download and the end-of-line there may be 190 different direct lines, caused by inter-related parents. As RM reconstructs the tree it gets from FS, it traverses many of the same couples repeatedly, and, for whatever reason (that’s a bug), there are some that it does not recognise as being already in its FamilyTable and it creates duplicate records for the identical couple. No duplicate people are created; the same pair are repeatedly added to the Couples List.
While I’ve not attempted a download of this scale, I did do a much smaller one (16 gens) from a person identified in your big 2022 RM8 download as having parents who were half-2nd-cousins-once-removed, leading to the duplicate-couples|duplicate-parents syndrome in her line. My new download produced identical results as far as I checked up the line confirming that this bug that we’ve identified now existed then.
The good news is that the cleanup utility that I referenced in an earlier post eliminated all but the primary FamilyID for every unique couple in your file - no more duplicate spouses|duplicate parents|duplicate family-type events. It took about 13 minutes. Here are the basic stats:
| Before | After | |
|---|---|---|
| People | 121,866 | same |
| Families | 165,126 | 57,662 |
| Events | 308,479 | 276,175 |
I can’t speak to other issues reported in this topic by @int13h in April. The author has noted “duplicate processing” which sounds related to the duplicate-couples|parents|events syndrome. The Marriage events issue might be related - not something I’ve noticed or been looking out for. You may pick up on some of those in people with which you are familiar.