I think investments counts as balance, if that is the problem.
Faucet can be claimed when your balance is zero. Maybe you have invested your balance in website. Which mean you don't have 0 satoshi in your account. Therefore, can't claim faucets.
Ok, so that is it... Thanks for your replies.
Would be nice to be able to claim on faucet even with an active investment, I let here my suggestion to YoloDice owner.

I agree with you. Investments freeze your money, so you don't have anything to play with. The faucet gives so little that the owners wouldn't lose anything by allowing investors to claim a few satoshi. I see no reason why they faucet should be blocked.