I'm not exactly sure what the deal is here, but the default udev rule does not work for me with systemd-udev-229-8.fc24.x86_64.
I modified the rule to match based on the ID_MODEL, and now it works...
SUBSYSTEM=="usb", ENV{ID_MODEL}=="KeepKey", MODE="0666", GROUP="dialout", SYMLINK+="keepkey%n"
KERNEL=="hidraw*", ATTRS{idVendor}=="2b24", ATTRS{idProduct}=="0001", MODE="0666", GROUP="dialout"