Yeah, it has been reported. It seems the devs have known about it for years. Here are a few posts regarding the issue.
[Pre-cue in the DDJ-400 + Xiaomi POCO F3]
[No sound latest android app samsung s22 pioneer wego3]
[Djay for android and USB audio for real stereo mixing + cueing]
[Need help with some audio issues (Galaxy 5 and DDJ-WeGo3)]
[Reloop Beatpad works but no sound]
[djay2, wego4, Android 7: headphones output actually routed to master]
[Reloop beatpad 2 w/ Samsung Galaxy Note 10.1 running lollipop 5.1.1 - no USB audio]
[Djay 2 + Reloop Mixtour - No sound]
[DJay2 (Android) and Mixtour)]
[Wego3 without sound on the pfl]
[Djay 2 + Tab S 10.5 + Wego 3 = No Sound]
[No sound/problem control Mixtour/Djay2/samsungGalaxieJ3]
[Reloop Mixtour s10+ sound not working correctly]
[Beatpad 2 cueing through android?]
[No Headphone sound/DJay2/Nvidia Shield]
[Pre Cue Headphones doesn’t work on Android 10 USB-C with djay 3.0.4 and Reloop Mixtour]