Issues with upgrade of CMS to 7.1 SP2

Hello Colleagues!

We've done an upgrade of CMS from 7.1 SP1 to 7.1 SP2 2 weeks ago and still experience many issues.

Every day we found  new and new problems with plug-ins, policies, filters and packages.

At this moment we have these problems:

1. we have many broken agents;
   1. Some agents raise exception on start;
   2. Some agents have broken plug-ins;
   3. Some agents are started, but receive no configuration;
2. We have broken plug-ins (Software Update Plug-in, Software Management Solution Plug-In, Inventory Plug-in and etc.)  on NS server (policies with corrupted references, mismatched programs for plug-ins packages)
3. System policies were duplicated or corrupted.
4. Some settings were changed to bad values (for example, complete and delta membership update scheduled task has been set to “start every 1 min” )
5. Some Software products and Software releases are hidden from view page.

Might someone already had experience to get it resolved.

I've searched tons of topics on this forum, but nothing is that match our case. Only part of it, for example:

Any help is appreciated!