Today I became aware of the Single Mode settings - specifically Single Mode: Track - which is a feature I've long wanted but didn't know was already available in Rockbox. Surprisingly, though, I've found that about 50% of the time it plays a very brief audible bit of the next track before actually stopping playback. I've tried to figure out if there is a pattern or particular set of circumstances in which the overrun will occur but I haven't yet found anything. It seems that given two specific adjacent tracks, it either will happen 100% of the time or won't happen 100% of the time, though I didn't test that exhaustively. In any case, I'm thrilled to have use of the feature, but I thought I should report the little bit of occasional 'slippage' in its behavior.
BTW - I was using an iPod Video 5.5 Gen (MA444LL/A) with an iFlash-Quad containing a single 256GB Samsung Pro Plus microSD, running Rockbox dev build cfd5ef8db8-230614.
Thanks.