Akai Force USB MIDI/SYNC Wonkiness

Hey everyone,
This is my first post on this forum and appreciate any bit of help/support.

Master clock: Force 3.1.1
Allen&Heath Zedi8 mixer/interface
external synths
class-compliant (powered midi hub)

When playing/launching clips while external synths are synced via MIDI Clock, the set tempo/BPM gets wonky and either 1. flits up/down between various micro tempos or 2. begins to slow down from set BPM until it ultimately stops. This occurs randomly. This is clearly a midi/sync problem as it doesn't occur when external synths are not connected.

When synths are connected, they appear in Preferences/MIDI/SYNC and Ports are (I believe) correctly configured; can play/record MIDI notes (Track settings are set appropriately), but the synths won't commit fully to following/slaveing to the MIDI clock.

Not sure how else to explain this. photos are attached:

Supplementary questions:

Does this tempo change happen on the synths only, or on the Force, or both? Does it happen regardless of which synth is plugged in? Does it still happen without the Zedi8 plugged in? Does it happen with whatever you can attach without the hub in the mix?

Koekepan wrote:Supplementary questions:

Does this tempo change happen on the synths only, or on the Force, or both? Does it happen regardless of which synth is plugged in? Does it still happen without the Zedi8 plugged in? Does it happen with whatever you can attach without the hub in the mix?

Thanks for the swift response!
So, after some deep sleep I woke up clear-headed to find the trouble:

Both Sync Receive and Send were shooting Midi Clock ("crosstalk").
Switching Sync Receive OFF fixed the trouble (obviously keeping Sync Send on Midi Clock).

FORCE remained fully in control as Master no matter the external synth.

Sleep, that knits the ravelled network of MIDI.

Glad you figured it out. It's usually something like that.