Lubuntu 20.04 as live-media uses the ID 132 for sambashare. After installation it creates the group sambashare with GID 1000, so the first user get UID:GID 1000:1001. Existing user data will be change to the new value, but only for the first user.
If more than 1 user will be created, the next users get 1001:1002, 1002:1003 a.s.o., but the existing data stay the way it is.
It would be nice, the group sambashare get a lower number.
That is a known issue.