Play Selection erratic, sometimes does not play

Something strange with Play selection: the red cursor just skips to the end of the selected annotation, but without playing anything.
It will randomly work/not work on certain annotations. Even two identical annotations close to each other can work differently. I cannot see any pattern to why some work and some don’t. It seems to be erratic. The behaviour is the same if I use the keyboard shortcut or the button for play selection. However, when I just play the file, all the sounds are perfectly aligned with their annotations.

I have only WAV files, no video. Running ELAN 5.9 on Linux Mint 18.1 Serena 64-bit, Kernel Linux 4.4.0-53-generic x86_64, MATE 1.16.2

Thanks if the Debugging team can tackle this one, as we are processing 1800 files and we mostly rely on Play selection for this work!

Best and stay healthy,

That is difficult to explain.
On Linux there are 3 media player “frameworks” available for wave files, the VLC based player is the default. This player can be a bit “jumpy” but the description of your situation sounds worse than what I would expect. But maybe you have selected a different framework? Either way, this is something you could try: one by one select a player framework in the Platform/OS panel of the Edit Preferences window (VLC, JavaFX, JavaSound) and see if that has any effect on the play selection behaviour (reopen the document after making a change). If any of the frameworks performs better than the others, you could stick to that one?