Horse that periodically bolts

What breed is it? Any idea who trained it to drive? (i.e. - Amish or non-Amish?) Was it driven as a single or as part of a team or 4-in-hand?

I agree it doesn’t sound consistent with EPM. The Shire I had that contracted EPM became withdrawn from human contact and very clingy with other horses. He got very weak from it - could barely walk let alone bolt. Is PSSM what used to be know as EPSM? I suppose it’s a possibility. Lyme or Bartonella? I do agree with others that the horse may have been in an accident and have some TBI or nerve damage. Or just mishandled at some point. IME people talk about Amish as being harsh in their training techniques but there’s a shameful number of non-Amish driving trainers out there that are frankly flat out abusive in their techniques. Our sweet old Percheron had a dent above his eye from being hit in the head by a piece of lumber or metal pipe by his first owner. That person was the owner of a well-known commercial carriage company in the midwest and no Amishman.