Sometimes if you go back to a certain page, it'll go back to the sP you had originally. Usually it'll go back to normal once you leave that page.

you get sP for posting on the forums. but like said if you press the back button it will go back to your original amount. if you do that, just refresh C:

oh wait. wow that's weird. not sure about it going down again after refreshing o.O

You get sP from posting on the forums.

Maybe it's your browser then. But hey, I could be wrong.