The bug
The lit redstone torch models in the repeater and comparator texture are missing their bottom texture. Actual redstone torches, normal torches (on a block or at the side of it) and unlit redstone torch models on repeaters and comparators (when the repeater/comparator is unlit or when the comparator is not in subtract mode) the bottom texture is in its place.
Since that texture actually can never be seen ingame unless in spectator mode, it should probably be removed for unlit torches instead of being added to lit torches.
How to reproduce
Place a repeater/comparator
Lit it (or put it in subtract mode for comparators)
Go to spectator mode
Go into the block under it
Look up
To see the difference, you can unlit it and look again.
Linked issues
Attachments
Comments
It is not visible in survival and it could very well be intended. But I noticed that when it is unlit, it has these textures (i.e. they actively intended to include this texture but they missed it in the lit version). So I believe that the issue should be reopened.
Ah, right, thanks for clarifying that. I completely missed the part in the ticket where it said that only lit repeaters and comparators are affected.
Thank you.

Shouldn't it be made so that these faces never render, since you can't legitimately see them?
Is that missing texture visible in Survival mode? I don't see a reason why it would need to be rendered.