I found an old message from Richard Stearn about the order of aplication to kill when performing ax25-down.
It may be interesting to take richard's remark for your ax25-down script.

Regards and 73s,

Bernard

----- Message Transféré -----

Date: Thu, 29 Sep 2016 18:55:14 +0100
De: Richard Stearn <richard@rns-stearn.co.uk>
À: f6bvp <f6bvp@free.fr>
Sujet: Re: waiting for ax0 to be free


Bernhard

I have just been looking at your ax25-down and noticed that you attempt
to kill ax25ipd along with beacon ax25d ax25rtd mheardd listen saxIgate.

ax24ipd creates a tty for use by kissattach much like mkiss. Based on
that I think you should be killing kissattach before you kill ax25ipd.