I had finished all my Pinnacles for this week on my Hunter, so decided to go around collecting my remaining Powerful rewards. I didn't pay much attention when I picked them all up, but once I had opened them all, I went in to character to find they were all -1 to my max power.
I checked the season pass and sure enough, the rewards were showing as 1257, but I reckoned (and DIM agreed) that I am 1258. I equipped my maxpower stuff and sure enough, I am 1258. I then went back into the season pass, checked again, now all showing 1258.
When I move my riskrunner (highest energy weapon ATM) off my hunter onto another character, the season pass drops back to 1257. Move it back, 1258.
I don't have any way to capture footage on this PC unfortunately, but the bug is 100% consistent.
EDIT: interestingly it does count it when it's in the vault...
#bugreport
Uploaded screen grabs, best I can do - grabs were taken with game live on one monitor, DIM open on other. Only action taken, move riskrunner from Hunter to Titan:
https://imgur.com/a/Frkexiy