SoundCue concatenator inserts delay between child nodes

I’m trying very simple setup: to play several short sound files one after another. My end goal is to create dynamic music via switching and sequencing these small patterns. However to do this I need them to be played seamlessly! But SoundCue inserts very noticable gap between the child nodes making it totally unusable.

Is this the bug? If not how can I play sounds seamlessly (C++/BP/3d party)? This is totally important for my project!

p.s. Music files are played perfectly (without gaps) outside of UE4.