Tight battery cable cable came off

So I went to start my car tonight and it turn on fine but when I went to actually start it it died, no lights or anything. I popped the hood and found that my positive cable had come off but it wasn’t loose so I had to loosen it to get it back on. My question is has anyone ever seen that happen and what would cause it?

Have not seen this but the cable may never have been on snugly and worked it’s way off.