well, then its simply flawed...,
better take it off and implement two or three differente captchas for the free roll page.
i bet that would be a preferably solution for everyone.
They adapt to any changes we make in a couple of days. Adding extra captchas would only buy us that and also frustrate genuine users.
currently my base prize goes up and down all the time (down again now) and on my end nothing changed
If you mean it jumping from half to full then this indicates your account usage is hovering around the level required to receive full base reward. If you mean it fluctuates by 1 or 2 sats then that is simply the USD to BTC exchange rate.
btw, im unaware of any bot that can actually solve recaptchas (not talking about those slow indian services..., watch youtube for it, LOL)
I'm not qualified to answer that but when wetsuit says there are botnets trying to bleed us dry and they adapt to everything he does to stop them, I believe him.