What is a Correlation thread responsible for? Does the thread maintain multiple queues? How are items in a correlation thread handled/grouped? What does an SLNet Correlation thread run-time error intend to indicate? Does it mean the thread is locked? If yes, what behavior could typically cause that?
Are there any available resources where I can find information about different threads in the SLNet processes to help me answer the above questions for all those threads?
That thread is responsible to handle correlation rules. If that thread is having a run time error then it means that the thread is stuck. It could be either waiting on a lock to be released before being able to continue or it could be waiting on an action to finish.
An example of such an action could be that a correlation rule has as action to run an automation script. If the configuration has the checkbox "Wait for the script to finish before continuing" active and it's an automation script that needs a long time to run then the correlation thread will wait on this to finish and an RTE could be generated (for example see task id 148050 that describes such behavior)
I don't know about an available resource that describes all different threads in the SLNet process. If this is the only RTE in the system (no external problem dragging this thread down) and the RTE doesn't clear after a period of time (=could be pointing to a lengthy action if it does clear) then taking a memory dump and asking software to take a look at it could give some more info on what the thread is waiting for.