Steps to reproduce
Trying to create a new item using either the “Insert New Line” toolbar button, or the Enter key on the Android soft keyboard, usually results in a note line below the item I already have selected, rather than a new item below.
If the existing item ends with a date, a new item is created below, as expected. This may be a red herring, however.
Only experienced with Android app, version 1.4.5 on Android 8.1.0.
Neither the Windows 10 app, or the in-browser list, have this problem.