Sounds as if a sensor is gooed up. If you are able to keep the dirt out of engines those engines will last forever! You need an introduction to your repair crew who if you butter them up will teach you all you need to know I kid you not! In one inexpensive visit you will get valuable know how so that you will be able to fix most 2 stroke/cycle engines! You will take that time of that visit to get a few back up filters, spark plugs. Air filter and gas filter. Have them just do a cleaning! Hang out with them if you can! Find a well to do small engine repair place, mom and dad? Never use any gas with ethanol. Use perfectly measured oil in the gas. I ran a business and doing this brown nosing with my chosen repair company saved huge bucks! Sweet hearts! Let's see, I am talking about 3 different repair companies. Paid off!!
Even though your trimmer is electric the same principles apply. That grease needs to be added and cleaned away. Are you hedging? (keep the bottom of the hedge WIDER than the top). Sharpen blades every single time you use it. That might just be the problem, gooed up reciprocating blades?!!! Don't use WD40. Use a silicone spray. Learn how to sharpen your blades with a file. Clean residue of plants and oil off the blades as you sharpen. Each time you finish hedging.