Symptoms

An error occurs when searching a SO based on a SharePoint list with a lookup column.
If you search with an ID for the lookup column id, an error:

Server was unable to process request. ---andgt Field with name " (ID)" was not found.
 

Diagnoses

Confirmed bug. TFS request submitted to fix (10/03/2015).
 

Resolution

Workaround:
1. Open K2 designer and navigate to the formview where the load happens
2. Add a parameter (for this example, I’ll call it paramFilter)
3. Add a hidden text box (for this example, I’ll call it fieldFilter)
4. Add an expression to fieldFilter (for this example, I’ll call it expFilter)
a. Set expFilter to only hold paramFilter
5. Open the rule that does the load
a. On the Input Mapping screen, uncheck the List Item ID
b. On the filter, add a filter that uses the List Item ID = expFilter
c. Finish
6. Save