SilverWook said:

Is it possible it's an artifact of the camera used in the transfer? 1970's video cameras were notorious for "trails" on bright light sources like candles.

Here are a couple of examples of the ghosting/light trails which is subtle on static shots but more obvious on high contrast moving shots. My sense also is this is a result of the original 1970s capture not the tape to digital conversion, but I know very little about this stuff really, so expert anaylsis would be helpful: