SugarCRM 7.9.2.0  upgrade failure

SugarCRM 7.9.2.0    what changed?

Upgrade out SugarCRM 7.8.2.2  to   7.9.2.0     works via the   web upgrade-wizard.

However,  once the upgrade is done,   some of the  SugarCRM modules no longer work.

Calendar  -  Shared.

Employees

Users

Server then has  mysqld  processes  that  spike to  100 %  and  never finish.

Tue Jan 28 16:44:01 2020 [3927][1][ERROR] Warning: Multiple links found for relationship users_team within module Users
Tue Jan 28 16:44:01 2020 [3927][1][ERROR] Unable to determine best appropriate link for relationship users_team