[PROBLEM] Gapless playback not working anymore on FLAC

[A.T.E.]

Software
XBian version: since 2017.02.24; latest tried 2019.04.19
XBMC/Kodi version: 17, 18.1
Overclock settings: none

Hardware
Device type and model (e.g. Raspberry Pi Model A/B 256/512 MB, CuBox-i i4Pro, ...): RPi2
Power supply rating: the usual 5 Volt, 2 Ampère
SD card size and make/type: Toshiba Exceria SDHC UHS1 16GB, but it happens on other models
Network (Ethernet or wireless): Ethernet
Connected devices (TV, USB, network storage, ...): TV, NAS, Hifiberry DACplus

Log files
Link to logfile(s): https://trac.kodi.tv/ticket/17375#ticket

Problem description:

Since Kodi 17.0 (XBIAN 2017.02.24 on a Raspberry Pi 2) the FLAC playback experiences a very short, but audible, gap between tracks. As far as I can tell, the gap happens at the beginning of the subsequent track. It happens on FLAC, but not on on MP3.

As you can see from the link to the logfile, I had opened a ticket for the Kodi folks. Since then, I have tried a version of OSMC (2018.12-1 running Kodi 17.6), and that one is not experiencing the issue. This leads me to suspect that perhaps this is not an issue of the Kodi source code, but of how it is built into an executable.

Now, I took the chance of the new Kodi 18 to try to come back to Xbian, but again, to my disappointment, the issue is still there.

So, I have decided to try my luck here reporting the issue to you; perhaps you will be able to have a look at it and understand the root cause. As I am not sure of the origin of this issue, before going to github, I am posting it here.

FYI, the last Xbian version that I am aware not to be affected by this issue is 2017.02.17 (Kodi 16), whose .img I keep as a treasure on my computer. The problem is that add-ons evolve, and they gradually stop supporting Kodi 16...

How to reproduce:

It happens on FLAC, not MP3. So, you need two consecutive FLAC tracks without silence between them (such as on a live album).