With Root Motion From Everything enabled, a Blend node gives different results when feeding it Animation Sequences directly or when first using a Cached Pose.
*Simple test project attached
Two scenarios, different results:
1. Two Copies of Walk Animation fed into A and B of Blend Node set at 0.5. Mesh moves 500 units
2. Walk Animation saved into 'walk' Cached Pose. Two copies of 'walk' Cache fed into A and B of Blend Node set at 0.5. Mesh moves ONLY 250 units
*Note: The animation itself moves the mesh 500 units.
Easiest just to check out the attached test project. Hit Simulate.
The mesh with an AnimBP that feeds Animations directly into the blend moves twice as far as the Mesh with an AnimBP that first caches the animations.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-16255 in the post.