I've been studying simplified for a while, and i'm going to start going through Heisig's remembering the traditional Hanzi. I switched my account to traditional before adding. However, when browsing the list i noticed a number of character's that look the same as their simplified forms, but show up as unstudied.

For example:
胡 hú: recklessly; non-Han people; why?
占 zhàn, zhān: occupy; seize; constitute, to divine; fortune telling
升 shēng: rise; hoist; promote; liter
只 zhǐ: only; merely; just; but
了 le, liǎo, liào: (particle for a new situation or completed action), finish; understand; clear
夠 gòu: enough; to reach

Is there a reason these show up as unstudied in traditional mode? i already learned them in simplified mode.

They appear because some of your examples are characters which have different (less wide-ranging) meanings when used as traditional characters. In the simplification process, there were some traditional characters with different meanings which were represented with the same character in simplified Chinese.

For example, 只 means only/merely in both sets. In simplified characters it also is the measure word for some animals. However, in traditional characters the measure word zhi1 is written as 隻. You need to know that you can't use 只 .

Similarly, in simplified Chinese 胡 can mean facial hair. 胡子 is facial hair. But in traditional Chinese, hu2zi is written as 鬍子.

For your last example, 夠 must be written as 够 in simplified Chinese.

@Kryby, thanks a lot for the explanations!