The new type of items that can cover any block face (glow lichen and skulk vein) do not regenerate at all.
These blocks are similar to vines but even more difficult, so I am not surprised that they struggle to regen.

I'm guessing it's just a matter of adding them here: https://github.com/nitnelave/CreeperHeal/blob/master/src/main/java/com/nitnelave/CreeperHeal/block/CreeperBlock.java#L158

Maybe there's a new API and we can dispense of that list, but I don't know.