Summary:
Armor stands react to splash potions or lingering potions. The following potions have noticeable effects:

1. Harming: Armor stand turns red, makes a player-like damage noise, and is knocked back. Doing this several times will kill the armor stand in a puff of smoke, and the armor stand will not drop itself. It does drop its worn items, however.
2. Poison: Armor stand takes damage over time as if it were a living mob.
3. Wither: Armor stand takes damage over time and dies as if it were a living mob.
4. Invisibility: Armor stand turns invisible.
5. Slow falling: Armor stand falls slowly.

Other potions have no visible effects for obvious reasons. In all cases, the armor stand will have potion particles for the duration of the potion effect.

According to Java splash potions or lingering potions should ignore armor stands.
Effects can be given to armor stands only through a command (/effect), but there will be no visible changes (particles, loss of health, slow falling, etc.) - which also works incorrectly in Bedrock now, as with potions, they generate particles, can die, have a slow fall, etc. when receiving an effect through a command.

Steps to reproduce:

1. Place an armor stand.
2. Throw any splash potions or lingering potions into it (except for the instant healing effect, as there will be no visible changes).

Observed results:
Armor stands receive effects, consume lingering potions, have particles and can have corresponding changes depending on the effect - poisoning, slow fall, invisibility and others.

Expected results:
Armor stands will ignore splash potions or lingering potions.

Notes:
According to Java, effects can be given to armor stands only through a command, but there will be no visible changes (particles, loss of health, slow falling, etc.).