Actually, under limited conditions, the duplicate facts will merge in RM6.
Required for facts to merge:
11) The date must exactly match.
12.1) The place must exactly match.
12.2) I don't use Place Details, but I'd expect that the place detail must also exactly match.
13) Descriptions must be blank.
Prevents facts from merging:
21) ANY variation in 11 or 12, above. Well, sort of -- a date of "1850" will merge with "ca 1850" or "abt 1850" and keep whichever was in the primary individual's fact.
22) ANY attached Note to either the primary or duplicate fact.
23) ANY info in either the primary or duplicate fact Description.
Alternate Name facts DO NOT FOLLOW THE ABOVE conditions.
31) Two EXACT alternate name facts WILL NOT merge (that is the merged individual WILL NOT have the combined sources from the primary and duplicate individuals).
32) If the duplicate individual has an Alternate Name fact (different from any Alternate Name facts in the primary individual), including exactly one Source, it might or might not be created in the merged individual, and it might or might not have a linked Source. I don't have any statistics on how often, but it sure feels random.
33) If the duplicate individual has an Alternate Name fact (different from any Alternate Name facts in the primary individual), including two or more Sources, it might or might not be created in the merged individual, and it might or might not have any linked Sources. I don't have any statistics on how often, but it sure feels random.
34) As to 32 & 33, it seems to merge incorrectly more often than not. Doesn't matter what the percentage is, because the RM results are inconsistent and unreliable.
35) The dropdown selector for AKA, Birth, etc. is also inconsistent in behavior when Alternate Name facts are merged.
My long-way-around procedure when merging individuals involves carefully looking at facts which I expect to merge, and edit either the primary or duplicate individual so that 11 (date) and 12 (place) are exact matches. After the RM merge, I may also place a comment or explanation in the appropriate fact Note.
Anything in the Description field for either primary or duplicate fact will force me to manually copy-paste that info and the linked Sources from the duplicate to the primary fact. Then the duplicate fact must be Deleted.
Alternate Names and their linked Sources must ALL be manually copied from the duplicate to the primary individual BEFORE the RM merge.
After the RM merge, I then open the merged individual's Edit Person screen, add fact Notes (if appropriate) and Sort Dates (wherever sequential events aren't sorting correctly because they happened on the same date. Sometimes I edit the Sort Dates and append -1, -2, etc. to the Sort Date (typically only if I have only entered a year for the event Date), or in other cases I adjust the Sort Dates to be sequential (for example Birth and Baptism may have both happened on 15 Jan 1841, but I'll revise the Baptism Sort Date to be 16 Jan 1841).
I typically set all occurrences of an Alternate Name fact to have the dropdown selector on AKA, but this is immaterial, since there is currently no provision in the RM Fact Type sentence language syntax to make use of the choice of the dropdown selection. THAT should be corrected -- it makes sense that if the dropdown selector has been activated, then it should be reflected in the Alternate Name sentence.
Since I've accepted GEDCOM contributions from a variety of cooperating researchers, this does mean that merging other's work into my RM database is typically a long-drawn-out process. I wish that RM handled the Alternate Name facts correctly (and consistently) and that RM would merge the fact Notes for two otherwise matching (date & place) facts. But it doesn't, so I try to work carefully, and when I get tired and sloppy I move on to something else....