This is in terminology and EFL built from head last Friday (2021-04-23). This has been going on for quite a long while.
I have "Scroll to bottom when a key is pressed" enabled. I have "Scroll to bottom on new content" disabled.
Have enough output to scroll the window. Scroll up and then move focus to any other window. After some period of time, terminology will scroll to the bottom. It can take any where from 3 seconds to more than 90 seconds to happen but it seems like it will always happen.
Disabling the "Scroll to bottom" option seems to have no impact on this behavior.