Interpret Deadlock And Fix It

I need to understand how this is possible, i.e. I would like to understand mechanics of this. Victim process is a big union-type query involves about 6 tables (Entity Frameworks)

Solution 1:

Looks like process 84 holds a shared-intent-update pagelock A. It is waiting for a shared key lock on B.

Process 77 holds an exclusive key lock on B. It's waiting for an intent exclusive page lock on A.

The next step is retrieving the SQL statements these processes were executing.