osx serial busy not detected

[tablatronix]

If I open serial monitor and a serial port is busy it just acts like nothing is wrong and does not detect this, it shows green and sits there with empty buffer..

Expected

[Mon Jul 22 21:54:25 2019]
$ pio device monitor -p /dev/cu.SLAB_USBtoUART 
could not open port u'/dev/cu.SLAB_USBtoUART': [Errno 16] could not open port /dev/cu.SLAB_USBtoUART: [Errno 16] Resource busy: '/dev/cu.SLAB_USBtoUART'

[tablatronix]

Looks like alot of this might be this, on osx I am having alot of deviot serial issues suddenly.

Inappropriate ioctl for device

[tablatronix]

I might have found a workaround, If I open send and send something sometimes it starts working instantly.

I still have no idea what the cause is, updated cp2102 drivers, reboots, some work some don't.. makes no sense. Using mostly cp2102