I noticed the price was down a bit, and then I found the news. ARI PR C is being called. All outstanding shares will be called 06/10/2019 for the price of $25 plus accrued dividends of $0.2223. Friday's close was within a penny of the total call amount.
The timing of the announcement was good in a way for me, as I was considering adding to my position as my next purchase. The better news is that I've found two possible replacements with a slightly higher yield that pay the same month, and they won't be eligible for call until 2022.