Weird no spark problems

Some weird stuff is happening with my nephews machine. He brought it into the shop to have mechanic solve a no spark issue. The mechanic fixed it and we brought it back home. Once home again no spark. We tried solving it with no issue so we loaded it back onto the trailer and brought it back to the mechanic. Pull into his yard and he walks up and it’s fires up right away. Nephew took it for a ride around his shop and no issues. Started it and stopped it several times no issue. Bring it home and park in garage It starts. Next day no start. Wtf is going on. Anyone have any suggestions on what to check?