All the research I’ve done leads me to believe that it has something to do with this Sohosin extension. I don’t know anything about it, but it seems to me to be another attempt at protecting php coders from themselves.
One thing that I did find out is that Suhosin sets max_input_vars to 200, this is an extremely small number. At a minimum, using ACF, this should be 2000. Not having this high enough can cause all kinds of strange behavior.
