The period from, say, 1850 to 1920 was simply a mess.
It is not unusual to see a woman move out from her parents as Andersdotter, then be registered as Andersson later on and towards the end of her life have Johansson as a married name.
In the patronymic system where daughters had -dotter names and sons had -sson names women did not have a married name. When a woman's name was converted from -dotter to -sson, that was her transit to a family name system. This usually happened before married names for women came in regular use.
It also happens that an Andersdotter moves to another parish and is registered as Andersson - and then upon a next move she is back to Andersdotter. This illustrates how much of these name registrations depended on the vicars - who were of different opinions about proper naming.
The result is a mess - but fortunately the sources are good, you can ususlly follow people all the way from birth to death.