In affected sessions Qtractor restores about 10 Insert Send/Return connections to mixer strips in non-mixer-xt.
This could be the cause for the XRUNs as well and cannot determined/waited for by Qtractor, I am afraid.
So a one second grace time could help. Of course I cannot guarantee that I am right and if it's complicated to implement it then don't worry.
In affected sessions Qtractor restores about 10 Insert Send/Return connections to mixer strips in non-mixer-xt.
This could be the cause for the XRUNs as well and cannot determined/waited for by Qtractor, I am afraid.
So a one second grace time could help. Of course I cannot guarantee that I am right and if it's complicated to implement it then don't worry.