[PROBLEM] Gapless playback not working anymore on FLAC

[A.T.E.]

Thanks for devoting some of your time to this issue.
I am thinking that either you could not replicate the issue, either you could, but you did not notice the gap, which is in fact very very short.
Just in case it should be the latter, I have shared one more file, which is what I hear when I play those two FLACs on my system.
If you carefully listen (perhaps using a headset as the audio quality is not the best) to this audio file, which I recorded with my phone, you can feel (between seconds 14 and 15, actually more towards 15) the gap happening: https://drive.google.com/open?id=17Oz5-PYPmjQcmBtAleGNBuVvyj1bi2Cu
The two FLAC files were played locally (i.e.: they were on the local SD card), so that I would discard any possible SMB or network latency.
Also, later I have disabled the Hifiberry DAC+ by restoring the /boot/config.txt file to its original settings. I played the two files again through the HDMI output and I could feel the gap.
At that point, XBIAN was in its “vanilla” state (i.e.: no add-ons) except for the old Confluence skin.
If on the other hand you could not replicate the issue, the thing becomes more complicated. It can be my system, but other people reported the same issue, and also the thing is not happening on OSMC (which has received a major system and Kodi (18.2 RC1) update some days ago.