When you enter a lava cauldron in survival mode you will take 2 hearts of initial damage and take 2 hearts till death, but in normal lava you will take half a heart of initial damage and take 2 hearts form there till you die.
MCPE-137685
Damage between lava cauldrons and lava blocks are different
Open
6
(Unassigned)
587527
Confirmed
Multiple
1.17.30.21 Beta, 1.17.30.20 Beta, 1.17.11 Hotfix, 1.17.10
Retrieved
Can confirm in 1.21.51 Hotfix.