Sorry for the obvious question: Is the toggle switch for double press turned on?
What Firmware version is your Styrbar? You can find it under the device via the Settings > Devices & Services > ZHA Integration → Devices > {Remote}.
I am running Firmware 0x00010024 with no issues (with the Double Press Down, at least.)
You might need to set up ZHA Firmware Updates to upgrade.
Also make sure your signal strengths are strong, and your Zigbee stick is separated from the host device (using USB extensions) and WiFi Access Points.