A tamed wolf with Health Boost 24 (totaling 120 health) at full health (120) will sometimes go back down to 20 health when the world is closed and reopened, losing all of it's extra health for no reason.

To reproduce:
Summon two wolves and tame one of them.
Run /effect give @e[type=wolf] minecraft:health_boost 1000000 24
Run /effect give @e[type=wolf] minecraft:instant_health 100 100
The tamed wolf will have 120 health on it's NBT. The wild wolf will have 108 health on it's NBT.
Reload the world a few times (Save & Exit -> Load)
The Tamed Wolves will glitch out and lose their extra health. Wild wolves, parrots, horses and any other mobs will not glitch out. Wild wolves will always be at 108 health after a reload, like they should.

To make it easier to visualize:

• Use a Health tracking scoreboard (running "execute as @e[type=wolf] store result score @s Health run data get entity @s Health" every tick)
• Or a health bar/boss bar datapack/mod

Extremely frustrating. #FreeTheWolvesMojang #LetTheDoggosSmile