I was trying to make a more aesthetically pleasing blood altar (using different beacons that give off different light, but apparently only the vanilla beacon works to make a tier 5 blood altar.

It'd be nice if chiseled beacons could work as well, since they're functionally equivalent and require the actual beacons to make anyway. :)

Edit: Also of note, probably caused by the same thing, are that chiseled glowstone and bloodstone also reduce the altar level, as they're not seen as valid blocks.

Crossposted at Chisel-2/Chisel-2#415 since i'm not sure which mod is at fault.

It is on BM's side but fixing it now wouldn't do much as it's not getting updated for 1.7.10 for now

Thanks for the info. Still good to fix it for the next release though, so i'll leave the bug open. 👍