My analysis was that it's only a limited number of built-in apps which belonged in the "other" folder which show this behavior in Launchpad in Catalina.
Steps I took:
1) take note of the apps which appear after the "other" folder in launchpad (also on the second page), and which shouldn't appear there but rather in the "other" folder itself
2) within the Applications folder in Finder, drag the apps you took note of to the "other" folder (you'll have to type your local password)
3) I tried this several times and it seemed like one or two apps weren't coming back in Launchpad after automatic "resets" of Launchpad, so I carried on the dragging and dropping from the Applications folder to the "Other" folder in Finder until Launchpad was "back to normal"
For me, the apps seem to remain in the Applications folder in Finder after I move them, but at least they don't come back in Launchpad, and it seems to be fixed for me, for a week or two now. In past months, the "reset" of Launchpad occurred everyday or so. I am still curious as to what prompts this bug.
Hopefully some of you will be able to build on this and perhaps simplify this process. Best of luck!