Aye, welcome to the hilarious madness known as "Cloudflare".
I've seen this crap happen on basically every Cloudflare-infected site I've ever been on. I'm going to take a wild guess and say that the admins of this site dont have all that much control over how bonkers the captcha goes.
This is just one of the many reasons why it's very rare that I use this forum anymore.
And no, Fnord, it's not just user "choices" that are doing this. What exactly causes Cloudflare to target people is unknown, but... well, I'll put it this way: I've had different results based on the LOCATION I'm coming from. If I were to use my laptop from the house in Wisconsin, for instance? No problems. If I use it from here, my main house? Cloudflare will spaz out. Every time. My posting style, and frequency, is not different between the two. JUST location.
Likewise, THIS PC also gets it alot (and this is a brand new machine with heavy security (note that the laptop I mentioned also is heavily secure) and almost nothing installed on it yet. Squeaky clean, in other words), while my older PC upstairs, which is made out of distilled crazy and is breaking down (and is probably infected by a variety of things. It's about as secure as wet tissue paper), will not get targeted. It just doesnt. Cloudflare's "security" will ignore posts I make when I use the extra loopy machine, and they will be posted just fine without me having to do a captcha.
None of my machines are set to block sites of any sort. The only "blocking" they do is to use Adblock, and they all use the exact same set of adblockers with the exact same configuration (since I've found it to be effective without being intrusive).
Note that Cloudflare is also capable of showing incomplete/broken captchas without you blocking ANYTHING.
Again, this is Cloudflare. It is madness. I've dealt with it so very, VERY many times now, and nothing it does surprises me anymore. Frankly, it's futile to try to grasp the reasoning behind the horrid thing.