Titan Shield Wall Leech not working

Essentially, my life leech isn't working. Mana leech is fine, and life leech is also fine when I'm doing low level content helping buddies, but not getting life leech in my T15 maps / pinnacle content. I have 1x roll of the modifier on my gloves, and it was working fine, until I did a passive tree respec yesterday (swapped to another build, and swapped back) and it stopped working, and can't for the life of me figure out why.

I am going to do a full passive respec and re-allocate points to see if there's an issue with a particular node, and will update post if it's fixed purely by not allocating something, or just by respeccing.