This comes from working through Bob Hastings' filmography. Both IMDb and BCDb list him as a voice actor for the Challenge of the Super Friends episodes, but neither list character(s) voiced. IMDb doesn't even bother with "Additional voices", just "credit only".
I'm erring on the side of caution and not including the episodes. The credits seem to be drawn just from the episode end cards which, IIRC, were identical for all the episodes regardless of which cast members actually voiced character in the episode.
This is a bit of a sticky situation. I think crediting him as as a voice actor for the Challenge of the Super Friends is fine, but yeah if we don't know which specific episodes he did work on, it's best not to include them any of them singularly.
That could cause confusion among the viewers of the site using us as a resource. However, I will work on tracking down the episodes he did.