I think I have seen questions before about people having two entries, but not sure if there was any one explanation.
I have a lady in my tree who was born in 1916, and was still single in 1939 living on her own. One record looks like a "normal" record, where she is listed with the neighbouring households on either side. The second record is on an headed sheet, the address box is filled with dates and reference codes and her surname has been misspelt, which seems to indicate that it has been mis-copied from the first record rather than from the lady's own householder's form.
This lady married five times!
She married her first husband on 11 Nov 1940, but he was KIA 3 months later. Both register entries have his surname added but neither has any corresponding reference code or date
Second husband married 31 May 1941. Both entries have his surname (in red), again no date but a red "M" in left hand column, possibly indicating marriage
Third husband married Q1 1954. Both records have his surname (in green) and date 30-9-61 and reference CR282 PLY. (Probably refers to Plymouth).
Fourth husband married Q2 1963. The "normal" record doesn't mention this at all, but the second record has his surname and date 22-9-65 and reference CR283 DX.
Fifth husband married Q3 1983 (he died in 1985). There is no mention of him on either record.
FindMyPast has the "normal" record indexed under her second husband's name ( with her 1st husband's and her maiden name in brackets, both mis-transcribed. The handwriting for her maiden name is a bit difficult to read I admit, but her first husband's name is in block capitals!). The transcriber has completely ignored the second husband's name, although it is quite clear in bright green ink on the record
The extra record is indexed under the 4th husband's name (as would be expected, as it is the last one on the record) with previous husbands in reverse chronological order with maiden name last. i.e Indexed as expected, according to FindMyPast system.
So it looks as if both records for this lady were updated in tandem until 1961, and then what I have referred to as the normal record abandoned, so I am curious as to what additional purpose the extra record served, did it get separated from the normal one, so did not get the 1965 update. And as to why her fifth marriage in 1983 never appeared on either record, when I understood that the NHS used the registers up until the early 1990's, is a mystery.
Any ideas?