Give yourself absorption. Then take damage at an amount to lower your health but not completely remove the effect. If you then reapply the same (or lesser) absorption value the chat will return the error `Unable to apply this effect (target is either immune to effects, or has something stronger)` but will continue to apply the effect reguardless.

Steps to reproduce:
Ensure in survival with cheats enabled and no absorption
/effect give @s minecraft:absorption infinite 2 true
/damage @s 6
/effect give @s minecraft:absorption infinite 2 true

You will be healed and the error will be thrown.