No wax on grooves. It sounds like a metallic click!
I've notice that my top limb, right beside the bolt hole, touches the riser when I mount it and string the bow. The bottom limb, when mounted, the gap is all equal. The top limb looks a tinny twisted on the thick part where it meets the riser.
I've been talking with Roger Fulton but he always advise me that I must get those bolts good and tight.
I'm using a LRU skinny string. I thought it could be from it but I've tried also with the original and it does it also.
Very occasionally it doesn't click, but in 10 shots it clicks on 9!