Did An Autocallable ETF Just Malfunction?

We have called out the ProShares S&P 500 Autocallable Income ETF (ACSP) as being more volatile than many of the other funds in the space; I believe it is because ACSP targets a relatively high 18-19% distribution rate. This is a relatively new niche, but we are working with the idea that the higher the yield, the more volatile the fund is likely to be. 

The fund went ex-dividend today for a whopper of a distribution. It should be like a catch-up dividend reflecting September and most of August back to the fund's inception. 

From Yahoo;

From the ACSP website;

To keep the math simple, if ACSP pays 18% annualized, then it would be 1.5% per month, so I would have expected the first distribution somewhere close to 2.25%, not 11%. I couldn't find a news release on this, so I asked Gemini if maybe one of the notes got called and they had to pay the redemption out, and Gemini guessed that that is what probably happened, but the math doesn't check out; it's too big for that unless a bunch of the notes got called early. Grok said that is not what happened; that the structure of the holdings could not possibly result in notes being called early. 

Grok gave a rationale for it being a catch-up distribution, but when I pointed out why the distribution is too big for that, it backed off and said, "We'll know soon" what happened. 

I don't think it malfunctioned. I don't know what happened, and I'll eat some crow if this was a malfunction, but I have to think that the explanation will fit into parameters laid out in the prospectus. But that doesn't let the fund off the hook and creates a very rough ride for anyone holding the fund.

JELM and IACL are much lower yielding than ACSP and much less volatile. 

The lower-yielding ones are not going to end up being horizontal lines that tilt upward; they will be more volatile than that, but I am quite certain they won't look like ACSP. That fund looks like a very difficult ride.