According to MC-205045 Players do not freeze inside powder snow cauldrons - Jira (mojang.com), cauldrons (apparently) should not inflict the debuff associated with the liquid inside it. This is further supported by the fact you cannot drown in a water cauldron, but when standing in a lava cauldron, the player will take rapid fire damage.
MC-255578
Lava cauldrons cause fire damage
Resolved
Works As Intended
0
MC-205045 was resolved as Won't Fix, meaning it would be working as intended if the issue was fixed. Therefore, cauldrons should inflict any effects caused by liquids inside them.