Spirit allocation bug

I have 2 companions and 2 herald skills. I have enough spirit (145) for all of them with 3 spirit to spare, but not all of them will active at the same time (50 + 24 + 24 + 44 = 142). If I swap a companion out (50 + 24 + 24 + 37 = 135) I can get all of them to activate at the same time with 10 spirit to spare.

What I find odd is that it works with "extra" spare spirit, and that I see percentages for a companion, like 35.4% instead of a flat spirit number.

Has anyone else seen this?

I created a google doc with a bunch of screen shots showing the behavior:

https://docs.google.com/document/d/e/2PACX-1vTHcfSk5uKQWG0WeoEyHCJgfYRCawuhUjqaLv-BXqCU25a3sbkJiQhu_fNKeM3qDS0adAYd_GKDZqp2/pub