OK, that probably wasn't the best example to use
However, having tried again with longer tracks (c. 5 min) I can confirm that I'm still getting the same effects that I reported earlier, namely that if logging is off, I get gaps in playback, but if logging is on, then playback is gapless.
I've attached another log file, but I doubt that it will tell you anything as, in this case, playback was gapless.
I have also tried reinstalling 25.0.80, and confirmed that I get gapless playback irrespective of the status of the logging flag.