After migrating to 126.96.36.199 it isn't possible to see the users in the MxAdmin -> Users form. There are 0 records and when clicking new I get an error: Error: duplicate key value violates unique contraint “system$user_pkey I also see that multiple sheduled evens are failed. It seems that all planned events are crashing. This is related to the same duplicate error constraint.
The first problem i had also. This is because the datagrid on the users is of type Account and not of users. So if you previously stored your users just in the user object then you need to make them of type Account and this should solve the problem. The second one i think i also had but i just deleted all constraints on the back-end database for that table and then redeployed.