UE4 animation freezes when trying to select a new slot

Hi. I have a problem. I have followed this tutorial for my character to perform combos:

However, I wanted my character to have his legs controlled by player. I followed this tutorial, with the default slot selected in animation blueprint, but the legs won’t move independently from arms:

I have tried to disable root motion. Now the problem is, anytime I create a new slot and select it, the character freezes in T pose. What to do to fix this problem ?

Also, no matter what I do

I solved the problem. It seems that changing the slot won’t update the animation preview. If you open and close animation montage window, the animation is displayed properly. Also, I didn’t selected the proper bone. I should have selected spine instead of hips in the layered blend per bone node.