Health boost effect makes players invincible.

I gave myself heath boost 10 in a repeating command block.
What I expected to happen:
When I got off the obsidian(I was using execute - detect), I expected it to run out and do nothing more

What happened:
The effect did run out however after that I was invunerable to all damage, including /kill,
though it did do the damage effect, just took no health.
Exiting and re-entering the world stopped the effect.

The command I used was:
execute @a[scores=

{tntrun=1}

] ~~~ detect ~_-0.1 obsidian -1 effect @s health_boost 1 10 true

After dying a few times, I became invunurable to all forms of damage