For example on one such incident (i stress, a different time, different plane), a MCP (mode control panel) was doing strange things intemittently like letting both pitch and autothrottle fight each other to maintain speed. Nearly all LRUs involved were changed before it was discovered that the windshield heat was not correctly grounded. This is located just a few inches from the MCP and is one of the big consumers on board. Tightening a few nuts solved the problem.
Based on my knowledge such kind of problem is not EMI. A badly grounded windshield heat cannot generate radio frequency which is the cause of EMI. Grounding issues are not related to EMI.