Spells like Suggestion and Charm Person have lines in their description that indicate the spell ends if you or your companions do anything harmful or damaging to the creature. For example, Suggestion has the following line:
If you or any of your companions damage the target, the spell ends.
And Charm Person says:
If it fails the saving throw, it is charmed by you until the spell ends or until you or your companions do anything harmful to it.
I've always taken this to mean that when you damage/harm the target the fact that you're directly damaging them causes them to be brought to their senses that they're under the effects of a spell by a hostile creature and so they 'snap out of it' so to speak. Essentially in my mind damaging the target triggers a 'saving throw' with so much advantage that they automatically beat the DC.
As such, my question is this: if the target isn't aware that I'm the one damaging them, does the spell still end?
As a Sorcerer I cast Suggestion on an enemy and tell them to take off their plate armor, and then while they're in the middle of taking off their armor I use Subtle Spell Metamagic to cast Fire Bolt at the same enemy.
Does my Suggestion spell then end even though there was no verbal or somatic indication that I was the one who cast it at them?
In my mind I don't think it would as long as I can convince the target that the Fire Bolt came from something other than myself and would therefore not trigger the new 'saving throw' with an auto success, but I'm curious to see what other people think about the situation.
P.S. I'm aware it's not actually a saving throw that's triggered I just can't think of a better way to describe it.