Electric lawnmower isnt likely to go all 'Maximum Overdrive' on you like the movie as it lacks the computer tech needed for things like bit flips. No it's more likely to catch on fire and burn wherever you store it along with it due to EM radiation causing the lithium batteries to spontaneously combust.
Teslas are just computers on wheels. Thus they can and will glitch during solar/geomagnetic storms. This is known. Its just near impossible to prove. So you have to look at Tesla accidents in aggravate not individually and look for patterns like failing to negotiate a curve and driving into an object for no apparent reason. Theres a reason Teslas get into more accidents than any other car statistically.
Impossible to prove but can and does happen. Can even be emulated in a lab setting.
Heres another example of it being claimed in the media that electromagnetic interference is causing Teslas to drive on their own without driver input. Case study of where this has been observed in other EVs posted below. Video of the Tesla driving itself is here: