This is common issue when you record vinyl/cassette and then cut the recording into pieces
The tracks were ripped from legit Canadian HMV CDs using dBpoweramp CD Ripper to FLAC. The FLAC is then converted to MP3, also using dBpoweramp. Lastly, MP3Gain is applied, and the tracks transferred to my MP3 player.
Could this be a tagging issue? As a test, remove tags from two tracks (that have previously exhibited the popping behaviour on automatic change) and then play them - if there's no pop then there's a tagging problem.
I'm thinking there might be APEv2 tags that ended up in the files, or perhaps ID3 tags written in a way that's incompatible with your player, or something else unknown that got added on there somehow. I don't think it'd be possible to figure out exactly what it is, without examining the files themselves, but that's beyond my skill.MP3DirectCut surely re-writes the MPEG stream when it does its editing, and seems to remove tags, based on what you say. So it makes sense for the pop to disappear in the "cut" files. Perhaps you could try right click -> Utilities -> Rebuild MP3 Stream in Foobar on the problematic files, and see if that will fix the pop?