Initial note erratically skipped

Hello,

Here's a problem which is driving me crazy. I've spent a couple dozen hours experimenting and also searching the Web to see if anyone else has encountered it. No luck in either case thus far.

I have a score with three parts: dulcimer, upright bass and percussion. During playback, the first note of the score is missed by some instruments, but completely at random. Sometimes, all three parts play correctly from the start, and at other times some of the three instruments skip their first note, in various combinations. I've not been able to detect the pattern.

The three parts have been quantized and I've made sure the Play Head starts from zero. Still, erratically the very first note of any or all of the parts fails to play.

By the way, I've tried different hardware synths (two different Casios, Yamaha DB50XG, Behringer Odyssey, etc.). The problem also shows up when using Fluidsynth as a plugin. And, I've also swapped different USB MIDI adapters, from two different manufacturers.

Having said that, aseqdump indicates the data seems to flow properly:

----Here's what I see when starting up aseqdump:

madamex@Gateway-T-1623:~$ aseqdump
Waiting for data at port 132:0. Press Ctrl+C to end.
Source  Event                  Ch  Data
  0:1   Port subscribed            128:0 -> 132:0
  0:1   Port subscribed            130:0 -> 132:0
130:0   System exclusive           F0 7F 7F 04 01 00 68 F7
130:0   System exclusive           F0 7F 7F 04 02 00 49 F7
130:0   Control change          0, controller 0, value 0
130:0   Control change          0, controller 32, value 0
130:0   Program change          0, program 15
130:0   Control change          0, controller 7, value 120
130:0   Control change          0, controller 10, value 65

----And here's what appears for the dulcimer part when I play the composition and stop it after several notes:

130:0   Control change          0, controller 0, value 0
130:0   Control change          0, controller 32, value 0
130:0   Program change          0, program 15
130:0   Note on                 0, note 60, velocity 127
130:0   System exclusive           F0 7F 7F 04 01 00 68 F7
130:0   System exclusive           F0 7F 7F 04 02 00 49 F7
130:0   Control change          0, controller 0, value 0
130:0   Control change          0, controller 32, value 0
130:0   Program change          0, program 15
130:0   Control change          0, controller 7, value 120
130:0   Control change          0, controller 10, value 65
130:0   Note off                0, note 60, velocity 0
130:0   Note on                 0, note 60, velocity 127
130:0   Note off                0, note 60, velocity 0
130:0   Note on                 0, note 60, velocity 127
130:0   Note off                0, note 60, velocity 0
130:0   Note on                 0, note 63, velocity 127
130:0   Note off                0, note 63, velocity 0
130:0   Note on                 0, note 67, velocity 127
130:0   Note off                0, note 67, velocity 0
130:0   Note on                 0, note 71, velocity 127
130:0   Note off                0, note 71, velocity 0
130:0   Note on                 0, note 72, velocity 127
130:0   Note off                0, note 72, velocity 0
130:0   Control change          5, controller 120, value 0
130:0   Control change          5, controller 123, value 0
130:0   Control change          1, controller 120, value 0
130:0   Control change          1, controller 123, value 0
130:0   Control change          2, controller 120, value 0
130:0   Control change          2, controller 123, value 0
130:0   Control change          9, controller 120, value 0
130:0   Control change          9, controller 123, value 0
130:0   Control change          0, controller 120, value 0
130:0   Control change          0, controller 123, value 0

The first note is note 60, velocity 127, and is a dotted quarter note.

I should mention that I only recently changed over from Cakewalk running on a DOS computer (!) to Linux Mint. Everything worked well on the old computer for almost 30 years, and I was hoping that Qtractor would do the same. I'm still a neophyte on Qtractor, though, and fairly new to Linux Mint as well.

If it makes a difference, I'm using the Qtractor 1.2.0-4.1 appimage, and my OS is:

Kernel: 6.8.0-47-generic arch: x86_64 bits: 64 compiler: gcc v: 13.2.0 clocksource: acpi_pm Desktop: Xfce v: 4.18.1 tk: Gtk v: 3.24.41 wm: xfwm4 v: 4.18.0 with: xfce4-panel tools: light-locker vt: 7 dm: LightDM v: 1.30.0 Distro: Linux Mint 22 Wilma base: Ubuntu 24.04 noble

I do have a work-around, but it really disrupts the workflow. If I shift all the tracks over one measure and insert a dummy first note at the start of the first measure, then everything works. I can trim off the phony first measure when done recording. But I'd rather things just work properly in the first place like they did with Cakewalk.

So, any suggestions?

Thomas Henry