Bounce to Track(s) missing some tracks

A problem I already had when trying to bounce a whole mix. Now I tried the "Bounce to tracks" option.
Track 1 - Audio mono
Track 2 - Audio mono + 1 FX Plugin
Track 3 - Audio mono + 1 FX Plugin
 
I select the 3 Tracks by selecting their "numbers" on the left on the tracks panel, the numbers become orange, the tracks and their clips are select in the region I marked before on the timeline. Then I start "Bounce to tracks", Target "Track 12 (an existing empty audio track)", "Stereo", "What you hear" preset.
 
In the mixdown on Track 12 the audio from Track 2 is missing completely. Tried 10 times in a row with various options.