GL.iNet MIFI 3g-modem on 18.06(.01) not working when LED triggered by interface

Hi all,
I have this strange behaviour that I don't remember having on 17.x on my GL.iNet MIFI.
I have a complete setup with mwan3 automatically bringing up my 3g modem when there is no wired WAN etc. etc. Because I haven't been using 18.06.00 long enough, I'm not 100% sure this has worked more than once, but after upgrading to 18.06.00 I made a backup of the complete config.

After upgrading to 18.06.01 I started to notice the router would not connect via 3g. The interfaces page would say "no such device" and there would be no /dev/ttyUSB* devices. Uploading the saved config again, did not change that. I was scratching my head big-time and noticed a factory reset and manually configured modem would make it work, so I started adding configurations back piece by piece. Lo and behold ... when I let the LED gl-mifi:green:3g-control be triggered by netdev/3g-modem, the modem stops working!

dmesg has this to say:

[ 1596.927576] usb 1-1.2: new high-speed USB device number 46 using ehci-platform
[ 1597.091455] option 1-1.2:1.0: GSM modem (1-port) converter detected
[ 1597.096764] usb 1-1.2: GSM modem (1-port) converter now attached to ttyUSB0
[ 1597.104188] option 1-1.2:1.1: GSM modem (1-port) converter detected
[ 1597.109969] usb 1-1.2: GSM modem (1-port) converter now attached to ttyUSB1
[ 1597.117330] option 1-1.2:1.2: GSM modem (1-port) converter detected
[ 1597.123153] usb 1-1.2: GSM modem (1-port) converter now attached to ttyUSB2
[ 1597.130563] option 1-1.2:1.3: GSM modem (1-port) converter detected
[ 1597.136249] usb 1-1.2: GSM modem (1-port) converter now attached to ttyUSB3
[ 1605.426155] 3g-ppp0: renamed from ppp0
[ 1606.613542] usb 1-1.2: USB disconnect, device number 46
[ 1606.617872] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 1606.625548] option 1-1.2:1.0: device disconnected
[ 1606.630672] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 1606.638183] option 1-1.2:1.1: device disconnected
[ 1606.703044] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[ 1606.709779] option 1-1.2:1.2: device disconnected
[ 1606.714841] option1 ttyUSB3: GSM modem (1-port) converter now disconnected from ttyUSB3
[ 1606.722454] option 1-1.2:1.3: device disconnected

When I set trigger to "none" everything works like a charm ... except for the LED, of course.

This is pretty weird. Should I file a bug somewhere, or am I doing something wrong?