Background scan not triggering

[zao]

Since Windows 10, I have unfortunately a small problem with that.

If I, for example, three songs new add and start the first new song, the
waveform is automatically generated. So far everything fine. But now
when I start the second and third new song, no waveform is generated!
To obtain a waveform for the second and third song, I have to start
twice new foobar (1.3.8). After each restart of foobar, I can only
create a wave form of the new songs!

[zao]

User claims that neither implicit scans nor explicit scans from context menu work until restart of player.