Hi there,
If you’re using the characters from the Third Person Template, they all come with "Foot IK Control Rig, which means, during playtime, their feet will be locked in the floor in order to follow terrain slopes. You just need to add a curve Disable LegIK to all animations that require feet movement without “foot IK” enabled. Usually jumps, dashes, climbs, rolls, etc.
I’ll print a screenshot showing how to do it.
Easier way, you can remove the Control Rig reference from your animation Blueprint. But that will disable all gameplay states.
The harder way: create another condition that, if playing montages with full body, disable Foot IK control rig, which will require more code.