Problems with udev rules

Yes, the group pludev is available and I also use it for another device. Reboot and reload rules doesn't change anything. It seems that the rule is not triggered at all.

Maybe this is of help, /dev/ttyACM0 does not have productID nor vendorID. It is available one level below.

udevadm info -a -p $(udevadm info -q path -n /dev/ttyACM0)        

Udevadm info starts with the device specified by the devpath and then
walks up the chain of parent devices. It prints for every device
found, all possible attributes in the udev rules key format.
A rule to match, can be composed by the attributes of the device
and the attributes from one single parent device.

  looking at device '/devices/pci0000:00/0000:00:14.0/usb3/3­-2/3-2:1.0/tty/ttyACM0':
    KERNEL=="ttyACM0"
    SUBSYSTEM=="tty"
    DRIVER==""

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb3/3­-2/3-2:1.0':
    KERNELS=="3-2:1.0"
    SUBSYSTEMS=="usb"
    DRIVERS=="cdc_acm"
    ATTRS{authorized}=="1"
    ATTRS{bAlternateSetting}==" 0"
    ATTRS{bInterfaceClass}=="02"
    ATTRS{bInterfaceNumber}=="00"
    ATTRS{bInterfaceProtocol}=="01"
    ATTRS{bInterfaceSubClass}=="02"
    ATTRS{bNumEndpoints}=="01"
    ATTRS{bmCapabilities}=="2"
    ATTRS{supports_autosuspend}=="1"

  looking at parent device '/devices/pci0000:00/0000:00:14.0/usb3/3­-2':
    KERNELS=="3-2"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{authorized}=="1"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bDeviceClass}=="02"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{bMaxPower}=="100mA"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{bNumInterfaces}==" 2"
    ATTRS{bcdDevice}=="0200"
    ATTRS{bmAttributes}=="c0"
    ATTRS{busnum}=="3"
    ATTRS{configuration}==""
    ATTRS{devnum}=="4"
    ATTRS{devpath}=="2"
    ATTRS{idProduct}=="5740"
    ATTRS{idVendor}=="0483"
    ATTRS{ltm_capable}=="no"
    ATTRS{manufacturer}=="STMicroelectronics­"
    ATTRS{maxchild}=="0"
    ATTRS{product}=="STM32 Virtual ComPort"
    ATTRS{quirks}=="0x0"
    ATTRS{removable}=="removable"
    ATTRS{serial}=="00000000001A"
    ATTRS{speed}=="12"
    ATTRS{urbnum}=="211"
    ATTRS{version}==" 2.00"
...