Modern Vespa

I recently got my Vespa back from the shop after a 7 year hiatus in the shed. They cleaned the fuel lines, replaced the spark plug, etc. It was in pretty good shape otherwise.

I drove it probably 100 miles over a couple weeks before the oil light turned on, stranding me. One trip on a trailer later, it starts again! Oil light off!

I'm understandably nervous to drive it to work given that I need to drive between buildings in the day (teacher). I checked the oil level, and it was perfect.

Has this happened to anyone else or does anyone have any insight as to wtf happened?

Hey,

first thing,
add 150ml of oil and go for a ride, then see what happens.

If your oil level is between the two marks then either the oil pressure sender is failing somehow or the oil pump has failed.

GTS oil pressure light issue: problem or not?
you can do a physical check of the sender - a pic of where it is is here:
Where is the oil pressure indicator sending unit on the GTS?

I have to ask: when checking the level so you screw the dipstick in? (Apparently many other bikes you don't ...)