Ok so I have a question, If the opponent had reflective shield and then he uses firebolt on mirror golem it would get hit right? Or it would still be reflected on the caster?
Btw cool idea.
Only one reflection. However, if you firebolt your own mirror golem you'll hit yourself.
Wouldn't it reflect off your golem then reflect off the opponent's shield and end up hitting you, so it'd be like they targeted you with the spell?
In general, things should only reflect ONCE.
This mechanic is usually put into place so that you don't get an infinite feedback loop of a spell trying to reflect back and forth an infinite amount of times.
To keep it simple, if the golem's reflect comes into place, it will not reflect again off your opponent's shield.