Anybody else have a spark plug cable blow off plug?

I was driving along and I noticed it was running rough, at a stop light very rough. Pulled over and the front bank left spark plug had no wire connected. Found it hanging and reconnected it, had a tight fit and stayed in place until I got home, about a half mile. I know it was put on tight because i put it on. What could cause this, a bad plug?

Gremlins.

What year, they made them 1970.5 -1978 or are they all guilty?

I have heard of spark plugs leaking compression. That would blow it off. I've even heard of them blowing the plug out. But, I think that was with a little more power than we have.

I've seen whole plugs blow out, usually because they were loose to begin with, have also seen leads fall off, usually because the innards are NG but have not seen a plug wite blow off.

It came off again today, it must be a bad plug, I installed a set of AC's about 3 months ago. It is the easiest plug on the engine to change. First time I had a plug do this, back in my teen's I had a boat with a 115 horse V4 and it blew out the whole plug in the middle of Biscayne bay. Thin aluminum heads = stripped threads. I cut a piece of a soda can into a strip and hammered the plug back in. Stayed in place for several outings.