There is a matrix job with 1 axis and 3 child jobs.
A label of slaves for execution is assigned via parameter using LabelNode plugin.
Initially there is no available executors in the system.

To reproduce:

• run the matrix job with the label parameter "exp_label1". Job is set to the queue;
• run the swarm slave and assign it the same label that provided in the parameter for the job: "exp_label1".
• the swarm slave appears in the list of executors and matrix parent occupies it. After that 3 child jobs are set to the queue forever.

I tried to use MatrixTieParent plugin but it looks it does not work correctly with NodeLabel plugin.