WP roles dropdown seen only in multisite no. 1

I think this is a WP multisite bug.

So if I go to network admin -> sites -> Edit site ‘No. 2’ -> users -> Add New User. – I can create a new user in site no. 2 and assign him any role from a dropdown – i.e. ‘subscriber’. But then if I try to change his role to author afterwards, I get the ‘you can’t change role for this users’ message. (I’m a network administrator).
Furthermore – If I go to site no. 2 dashboard -> users -> the ‘role’ drop-down is EMPTY (!). Same is if I click ‘create new users’ link there.

But this do not applies to site no. 1 – in that site I can change roles. Also if I go to site no. 4, 5, 6, 7, 8, 9, 10 – I can see roles drop-down there as well.

So the roles drop-down is empty only for sites no. 2 and 3. The only difference between sites are that site no. 1 – was original WP site (1,5 year ago), sites 2 and 3 were create also a year ago. And sites no 4-10 were create over last month. So sites 2 and 3 came over all year update process.

So how to get back roles for those sites? There is no ‘reset roles’ button.