Hostile mobs spawning in light levels 1-7 after 1.18

i dont understand this issue, do you mean "light level" as "block light level" (light from light-emitting blocks such as torch, lantern, etc.) or "sky light level" (light from the sky)?

Sky light level

well, that was intended, mob spawning depends on block light level, not sky light level

⚠️ Please do not mark Unreleased Versions as affected. You don't have access to them yet.

_{-- I am a bot. This action was performed automatically! If you think it was incorrect, please notify us on Discord or Reddit}

⚠️ Please do not mark Unreleased Versions as affected. You don't have access to them yet.

_{-- I am a bot. This action was performed automatically! If you think it was incorrect, please notify us on Discord or Reddit}

Actually, it depends on both: sky light must be 7 or lower, while block light must be 0.
The changelogs specifically said block light, this is intentional.

MOB SPAWNING
Monsters now only spawn in places where the light from blocks is 0 (sky light still prevents spawning like before)

https://minecraft.net/en-us/article/caves---cliffs--part-ii-out-today-java

⚠️ Please do not add Affected Versions to resolved reports.

Have a look at the Resolution and the comments to see why this ticket has been resolved. If you think this ticket has been resolved erroneously you can contact the Mojira staff on Discord or Reddit.

_{-- I am a bot. This action was performed automatically! If you think it was incorrect, please notify us on Discord or Reddit}