Sound Cue: Noticeable gap when switching between sounds

I have a couple of sound effects cues wherein I have set up two sets of sounds. In one of the cues there is a set of 3 sounds (~3secs each) that are randomized, looped, then send to a mixer; there’s also a set of 2 sounds (~4secs each) that are randomized, looped, then mixed. For some reason when this cue is played the 3 sounds will switch between themselves seamlessly, but the two have a noticeable gap/jump when they switch. I’ve checked the sound files and they’re as they should be, and I’ve tried placing the looping node AFTER the mixer but this cause the shorter samples to switch whenever one of their samples finished AND when one of the longer samples from the other set would come to an end (meaning an obvious cut during the clip).

The second cue I have is of 3 sounds (~1sec each) being randomized, looped, and sent to a mixer, alongside one single sound (~2secs long) that loops itself and goes to the mixer. With this cue I have the same issue as above with the single sample looping fine but the three samples having a gap/jump whenever they switch.

Is this a known issue, or are their any known workarounds? I’ve discussed this with a fellow sound designer but we both ran out of ideas on how I may be able to fix the problem. Thanks.

+1 for me. UE 4.8.3 OSX10.10.5 . Is it a mac issue or an older engine issue?

Still no solution to this in January '19, UE4.21.1