If I make an automation item with a sharp transition, it appears that there is a short invisible ramp (about 12ms long) from the previous value to the new one: as shown in the gifs, the tooltips show these "ghost" automation values.
The problem appears after both automation item borders (on the inside and on the outside, as shown in the gifs), and with any kind of transition (my gifs show only from loud to quiet because it's easier to confirm the problem by hearing the short "pop").