Hey brycesheridan,
Judging by your screenshot, MobSpawnESP seems to be working as intended. MobSpawnESP is highlighting the areas where mobs can spawn and showing nothing around the torches you've placed. Also, it looks like you've disabled the "Depth test" option, which allows you to see the spawnable areas in caves and behind those trees.
I've also tested this myself and confirmed that both MobSpawnESP and the "Depth test" setting are working correctly in Minecraft 1.20.6.
Hope that clears things up!