Symptoms

The following error is being logged frequently in K2 host server log:

"Error","SmartObjects","10702","Error","SourceCode.SmartObjects.ServiceBroker oExecuteSmartObject]","10702 An error occurred in the %SharePoint 2010 SI name% service instance. The request was aborted: The operation has timed out."
 

Diagnoses

You have specific service instance name in this error message which allows you to locate affected service instance in SmartObjects Services Tester (default location: "C:Program Files (x86)K2 blackpearlBinSmartObject Service Tester.exe") and try to reproduce this error using it.

In this specific case we see "The request was aborted: The operation has timed out" which is with high probability indicates that GetList method is being executed against extremely large list without filters applied/with too broad filter (the fact that some of your SharePoint lists have increased/non-default list threshold configuration may be additional indication of that).

Additionally you can check SharePoint ULS logs to check if anything logged on this side.
 

Resolution

Most likely at some point in the solution get list method is being called against large list without filtering it and this call causes time out errors. Investigate/verify as described above and correct by means of configuring filtering.