The Linux ttyACM0 drama - more details after a lot of experimenting

Hi,

I'm necrobumping this thread too. I was working with Arduino IDE on my Arch Linux without problems, now afrer some time I'd like to work on some new project but I can't upload the sketch.

this is standard 'state' of the /dev/ttyACM0: crw-rw---- 1 root uucp
But when I started upload, avrdude (or whatever else) is disconnecting USB and in moment when it tries to write permissions are: rw------- 1 root root

So even if my user is in the uucp group in that moment the device is set for root:root

dmesg:

[  313.042695] usb 2-1.2: USB disconnect, device number 3
[  313.253085] usb 2-1.2: new full-speed USB device number 4 using ehci-pci
[  313.352387] cdc_acm 2-1.2:1.0: ttyACM0: USB ACM device
[  321.234517] usb 2-1.2: USB disconnect, device number 4
[  321.439445] usb 2-1.2: new full-speed USB device number 5 using ehci-pci
[  321.541392] cdc_acm 2-1.2:1.0: ttyACM0: USB ACM device
[  457.935108] usb 2-1.2: USB disconnect, device number 5
[  458.176629] usb 2-1.2: new full-speed USB device number 6 using ehci-pci
[  458.275465] cdc_acm 2-1.2:1.0: ttyACM0: USB ACM device
[  466.126812] usb 2-1.2: USB disconnect, device number 6
[  466.332977] usb 2-1.2: new full-speed USB device number 7 using ehci-pci
[  466.435061] cdc_acm 2-1.2:1.0: ttyACM0: USB ACM device

my kernel: 4.11.9-1-ARCH
Arduino IDE: 1.8.3

lsusb:

Bus 002 Device 007: ID 2341:8041 Arduino SA

Nor this udev rule doesn't solve this problem:

SUBSYSTEMS="usb", ATTRS{idVendor}== "2341", GROUP="uucp", MODE="0666"

Any hints?