Gta signal jammers glitch

so i was doing the signal jammers thing in gta and after i destroyed 20 i got my saving the point i was at in my video, the next day, i was only and 10, i assumed this was a visual glitch but after i finished the vid, i was only a 40, i went black and checked out the first 20 and they were not there, is this some glitch? i’ve tried restart