So strange. This all HAS to be cafe related. Doing some reading this morning manufacturers looked to be getting a considerable bump in their cafe mileage numbers for each FFV model they produced. This phased "down" up to model year 2019. That may explain why we don't see as many today. Shame since the fuel is a renewable energy (corn). I remember during what I saw as the height of FFV production, like 2011 - 2015(ish) it became a big political thing about using food (corn) as a fuel, and there were questions on farmers being incentivized to provide it to fuel companies rather than food production.
https://www.nhtsa.gov/sites/nhtsa.gov/files/2015sae-powell-altfuels_cafe.pdf - the meat is on slide 5 and shows the calculation used that would increase cafe numbers for alternative fuel vehicles. I didn't see a date on this though scanning through it.
For reference, here's the timing maps from the Dodge Caravan FFV calibration I referenced when working on my Hellcat. Notice the huge bump in mid range timing in the alcohol table.
