Steps to reproduce:

1. Administration - Queue
2. Click "Details

Result:

On the queue page 2 active checks are queued, but details doesnt consinst any information.

Expected:
2 active checks stucked

Solution:

After some sort of brainstorm we've found that this stucked checks are LLD rules with Zabbix Active type. Need to fix this to allow LLD rules appear in queue.