Health Boost completely reset if applied again

The bug

If you apply the health boost effect and apply it again, the hearts you gain will reset.

How to reproduce

1. Run this command:

   /effect give @s minecraft:health_boost 10000 1
   

2. Wait a little for having more than 20 health points (1 health bar)
3. Run this command:

   /effect give @s minecraft:health_boost 10000 2
   

What it does

The health is recalculated to have a maximum of 26 health points. If we have more than 20 health points, it resets to 20.

What is expected

We should keep the extra hearts over the max, since we got a greater health boost level.

Note

This is only tested with potion effects, and not items that have the Max Health attribute.