OK so you have quite a few duplicate rows in there (newer releases of LXD prevent this happening in the future).
You need to create a file called /var/snap/lxd/common/lxd/database/patch.global.sql and inside put lines to delete the duplicate rows by ID (leaving just the ones you want).
e.g.
DELETE FROM networks_config WHERE id = n
Where n is from the first number column on the SELECT * FROM networks_config; output.
So in this case I can see you have multiple rows for ipv4.address:
1|1||ipv4.address|none
4|1||ipv4.address|10.11.12.1/24
9|1||ipv4.address|10.11.12.1/24
12|1||ipv4.address|10.11.12.1/24
17|1||ipv4.address|10.11.12.1/24
So I would add:
DELETE FROM networks_config WHERE id = 1;
DELETE FROM networks_config WHERE id = 4;
DELETE FROM networks_config WHERE id = 9;
DELETE FROM networks_config WHERE id = 12;
Leaving just the row Id 17.
Then repeat that, adding additional rows, for the other duplicated config fields.
Then restart LXD and that should fix it.