Light block updates are- quite strange

So, i was playin' 'round, just making an underground village, but as i hate torches, i started placing LIGHT BLOCKS, when i suddenlly noticed that their updates are- quite querky. (watch video)

how to reproduce:
1. Go to a dark spot
2. Place a Light Block
3. See that their numbers and sprites dont update correctlly

Result:
Strange numbers and impossible values (i guess?)

Expected result:
Instant updates to avoid confusion

Video: (too large for upload)
https://drive.google.com/file/d/1j2tpfkXy5JD4lwfESLGuKhTm1OLg6El3/view?usp=sharing