Smaller lift on the intake due to the loose stud would probably show less compression than it would if it were the exhaust valve.
I wouldn't think either valve would be damaged in any way by the reduced lift. Exhaust valve faces/seats can be damaged from not seating well and exhaust burning a groove in them ... but your issues is the opposite of that, it was seating too much
Basically if the intake valve lost lift then the cylinder would not draw in as much air and the compression would be less. How much less I don't know since the cranking rpm is so slow on a compression test.