If the HID-Button-ATTiny85 is already attached to an USB port before the PC is fully started it will not be recognized.

Remark: unknown if this can be fixed because this might be an issue of the Micronucleus bootloader or more likely of the DigisparkKeyboard library which does not try establish USB communication again after the PC has started its OS

Workaround: pull & plug HID-Button will restart it correctly as USB device