Not sure it's bugged but I did some talking with another experienced templar. He has 41 points into bastion, which he said is about 13% on the passive description. His blazing shield is at 29% of his max health. I've got 8 points into bastion which is 4.2% on the passive description. My blazing shield tooltip says 27% of my max health. 33 points is only 2% difference?
It seems to me that it isn't worth putting points into the bastion passive as a templar. Blazing shield is still one of our best skills as of now but, I probably won't ever put points into bastion again if it's such a minimal difference for so many champ points.
Templars.....always getting the short end of the stick
Bastion isn't worth it as a templar. The most i have gotten in PvP is 30% with 63 points in it. Now I have 16 points and have the typical 27%. I know PvP nerfs shields and damage etc. so more testing can be warranted, but As @Akinos said putting points into Bastion simply for blazing shield isn't worth the CP.