Seems when you try to repair 1 thing, you can break something else
Momento backpack works ok until you get full-stack. Next, this backpack keeps working as intended (probably for around 5 min) until stops Buff icon looks ok, you still get extra armor for "kill confirmed" but HP regen not working. You need to "reset it" by equipping another backpack and back to Momento and start collecting "kill confined" again. Worst thing: you have no visual info when this backpack is "broken" - died so many times today, before I got what is wrong.