Was it always this way? I just switched to Opera/Android and I've noticed that will work if I force the LP autofill app via the pull down quick menu at the top of the phone (the 3 dots). Certainly not every time, but it does work.
I did notice that the LP app just recently started notifying me to enable the accessibility services, but they have always been enabled. This was before I switched to Opera, but could be related if this is new behavior for the app.
What's your droid flavor? I'm running the latest version of Pie (v9 - update 4/5/19) on a Pixel2.