Hi Arlo,
I had an issue at my last gig where my patches weren't changing correctly, so thought I'd share it here in case others have the same issue.
I use Sysex messages to change the mode (Patch vs Peformance/Combi) on my keyboards prior to sending Program Changes. Since it's a common setting, I have a couple of MIDI Presets that contain the Sysex messages that I add to song presets as "Attached Presets". I've been using the MIDI Preset Order to make sure the attachments and/or sysex message are sent first, then the Program Control messages.
That's worked fine for years, but recently stopped working. I found that, while the keyboard was changing modes, it wasn't then also changing the patch/program. I tried several adjuments It wasn't until I went into your Release Notes that I noticed the new Serial Queue feature and turned it on that things started working again. So I guess the Program Change was being sent in parallel and being received before the keyboards changed modes until I turned on Serial Queue.
I thought I'd share it in case anyone else has the same issue, or in case you didn't intend to override the MIDI Preset Order in that way.