Hi,
I have the same problem as what Pasteta explained, for me it happened today. And I also was at my Garrison before I joined the battleground. Below few screenshots, 1 with the Honor Talents got resetted, and the other one with the "Honorable Kills" section at Achievement Points. I was at Prestige level 1, with 27 honor levels (if I remember right) towards Prestige level 2.
I hope there is a solution to fix this.