Now that you mention that the problem only presents when the DCS App is used and not when using the remote, the issue can only really be due to one of the following:
- The DCS App is at version 1.1 or 1.2 and the WIU is at firmware level 1.0, or the DCS App is at version 1.0 and the WIU's firmware is 1.1.
- If operating the WIU in Home mode, there's a problem with the WIU communicating with the router.
- There's a cabling issue between the WIU and the TIU.
- The WIU or the TIU are defective.
More detail regarding the above bullet points could prove useful.