loves you more than you will know
We have four toilets so I'm quite familiar with how they work. The tank is the only complicated part consisting of a fill valve and a flush valve. That's about as simple as it gets other than leaks and sticking handles. Toilets have been around a long time and the engineering by now should be perfect. Not so.
For the last few months one of our toilets got haunted and would mysteriously start flushing once in a while. No dogs or cats or little kids. No chain or debris blocking the flapper. No sticky handle. I changed the flapper. Still haunted. I changed the entire flush valve assembly. Still haunted. I then examined the flapper and found that it was incorrectly seating every so often because the arms were made of soft rubber and the connection had a lot of free play. So I installed a flapper that had plastic arms which eliminated incorrect seating. The ghost went away.
As you can see from the flapper the seating was not regular every time.