We have started seeing Runscope tests on public cloud engine, and also on-prem engine, being queued for 10 min, or more and not getting executed as scheduled.
Our investigation found that there were many stale test runs from multiple remote agents across teams, which had been stuck, and backed up for a very long time. Those were "blocking" the newer ones from running as scheduled.
Component : BLOCKMASTER
Runscope allows up to 200 concurrent tests. It is very important that you monitor your test load and ensure that you are not exceeding the 200 concurrent test limit. Whenever this occurs, the overflow tests will be throttled, which causes the delay of the tests being executed. If you are experiencing this type of behavior, you need to distribute the test load across multiple buckets.