Peter, such a shame that your Fujis were not able to satisfy the demanded performance. Although, a 100 images per battery is nothing like anything I have heard before or experienced, I can imagine that conditions and settings have resulted in this poor battery life.
Not sure if anyone mentioned it yet, but I have noticed a significant difference in performance between the W126 and W126S.
Although on paper the only difference is design and heat resistence, my X-Pro2 last significantly longer on the S battery. Moreover, when my older batteries (non S) are dead according to my X-Pro2, I can still get about 50-100 images when I put then in my fuji X-E1. This leads me to the conclusion that the older batteries are not able to always supply the power demand of the X-Trans III generation bodies. Moreover, since the batteries provide better actual powerleveldata to the camera, they really get emptied completely.
Since the X-T2 is the most powerhungry fuji body and you were using older batteries with deteriorated life, I can image that the batteries already indicated to be empty while they were not really (for other bodies).
Have you notices a significant difference between the old and new batteries?