What would you imagine the ability “On Escape Heal” does? The word “Heal”, first introduced in the ability “Swap-in Heal”, suggests it involves regenerating 25% of the user’s max HP.
Since Entelomoth, the only creature with the ability at present, is a hybrid of Entelodon, one of the creatures with Swap-in Heal, this is a logical assumption.
But is it correct? Well, yes, but actually no.
As you can see, the release notes describe the ability as regenerating 50% max HP, more like “On Escape Regeneration”, as it were.
This fits with what we see in-game, but the in-game description of the move says otherwise.
Based on the name, logic would dictate that the release notes description is wrong, and the mechanic in-game isn’t working as intended, leaving the in-game description as the only reliable source.
However, it is also possible that the name “On Escape Heal” is an intended misnomer, which caused some confusion with whoever was in charge of the in-game description. This would mean both the release notes and the in-game mechanic are as intended.