Indefinite Absorption Hearts

Vanilla Survival:
When eating a Golden Apple right after using a Totem of Undying, you will receive an infinite two absorption hearts even after the Absorption effect has worn off.

Eating a Golden Apple after the Absorption effect wears off will add two additional absorption hearts for a total of four. Absorption hearts return to two after the Absorption effect has worn off.

How to recreate:

• Use a Totem of Undying (which gives the Absorption 2 effect)
• Eat Golden Apple while effect is still active (to gain Absorption 1)
• When Golden Apple's Absorption 1 wears off, you will have two absorption hearts left

This works with any level of Absorption. The amount of absorption hearts left is always two less than the absorption level.
For example: absorption 3 gives you six absorption hearts, if you eat a golden apple while the effect is active, then wait for both absorption effects to wear off, you will be left with four .

 

After further testing, it seems like giving one's self a lower level Absorption level while a higher level of Absorption is active, will leave the player with infinite Absorption hearts equal to:

Amount of higher level Absorption hearts - amount of lower level Absorption hearts.

For example, give yourself Absorption 6 (12 hearts), and then give yourself Absorption 3 (6 hearts), you will be left with 6 Absorption hearts that will remain indefinitely (until you take enough damage to remove them.