I don't have the answer to your question, but I was once doing something, and inadvertently pushed the button that said to schedule a regen tonight. So as you were looking through diagnostics or menus, maybe you accidentally did that.
I sure would put a whole-house cartridge filter before the softener. I would put a 3-valve bypass around the filter, or get a filter housing with a built-in bypass. A 200 micron filter screen, or even a wye strainer (maybe 200 microns for one with a finer sc), would have been more than fine enough, but I like a big (lower pressure drop) cartridge to not only take out rocks, but to take out finer stuff.
https://upload.wikimedia.org/wikipedia/commons/a/a0/Wentworth_scale.png is a little hard to interpret initially because there is a lot of information. 200 microns is 0.200 mm. When you see mesh size quoted, that will normally be the US standard mesh.