This have been the case since couple of month back and ever since ReCaptcha have been pretty much useless for fighting off bots. As some have advised FunCaptcha, I would like to say that it's not an exception as well and bots have got in as well. So far what I'm noticing is users who use faucetbox script are mostly affected by bots so I think some modification is needed on script for sure and lastly don't even bother to use those click buttons here and there before get reward buttons pops out because that won't fight off bots as well. The code itself is the problem here.
I totally agree with that. If someone is using FaucetBox script - there is no captcha that will help.
By switching captchas is possible to get only temporary effects - maybe max for a few days. Sooner or later bots will attack script and it will clear faucet.
Edit: Only blocking bots by IP or all lists of wallet addresses can help.