Help with debugging an unwanted sound glitch

==> Never mind: It has now stopped whumping. The stopping on its own is more curious to me than the glitch itself.

I finished the How to Make Progressive House project. Loved it. Coming back to my version, however, I notice that a mysterious „whump" happens twice in the song. I’ve been trying to get rid of it but am now stumped.

The whump happens at Live’s marker 105 (3:15), seemingly on Track 12. Track 12 has a Sylenth and multiple devices (AutoFilter, etc.). The whump happens when Track 12 is solo’ed. => But it also happens upon Export if Track 12 is muted. There is a similar part of the song at 161 (5:00). The whump happens there as well. Here is what I’ve tried:

when I „File" / „Export Audio/Video" the project to a .wav format, I can see the glitch as a spike in my sound editor (When converted to .mp3 format the glitch is essentially inaudible.)

still happens even if I disable all devices after the Sylenth

still happens even if I swap in an ANA for the Sylenth

still happens even if I cut some time around the spot (eg: cut 103-107)

is not audible if I turn off all Track Activators (hey, it was worth a shot)

is not audible if the lead-in before 105 or 161 is tiny (eg I don’t hear it if I start at 164.4.4). (Phrased differently: It doesn’t happen with just 1/16th note, but it does happen with 2/16ths or greater.)

the glitch shouldn’t be a host resources problem – have 8Gb RAM, plenty of hard drive space, and am running the latest Live (8.3.1)

Can anyone tell me what’s happening? Thanks!

Here is a link to the Project (38Mb, .zip format)