Mine only does it sometimes aswell, 99% of the time when im trying to show someone how its done Done it a few times litterally giving it a tiny bit of juice pulling off aswell

Tends to have patches, it'll be doing it consistently for a while then stop, but its progressively getting worse, it is funny to see all the drunks in town jump out of their skin though

That's what my money is on, but do the tests anyway incase its not.

Thats the spirit, at least have a go!! No point paying some other monkey to do it if you can do it yourself, AND you know EXACTLY what you've done

Let me know how u get on