"Is there meat in your potato salad?"
Translation:Je ve vašem bramborovém salátu maso?
Using "Je maso ve vašem bramborovém salátu?" at a restaurant (e.g. by a vegetarian) without some specific preceding context is really clumsy. You would be understood, but this order is primarily for asking "Is the meat in your potato salad?", that means asking where it is. We know it went somewhere and we are wondering where it ended up.
You are focusing on the final "in the potato salad" instead of the "maso". Using "Is there..." is pretty specifically asking for existence or presence of something (and the something is the focus, not the location)..
We can discuss whether it is marginally allowable anyway, but accepting it will never make it a good translation.