Responding to externally triggered changes to the blind should work. The wifi bridge uses broadcasts to notify of changes happening from the outside, such as remotes or controls on the blind. These broadcasts however do not travel across different networks, long hops or can even be blocked by certain router or switch settings. For instance IGMP snooping is known to cause problems.
You can experiment with the options in the Homey app a bit to see if there is a cause from within the Homey Motion Blinds app preventing the broadcasts being received.
To counteract possible problems if the reporting does not work, the app queries the blinds at a very slow rate (think once or twice a day). The manufacturer of Motion Blinds explicitly asks not to poll at a higher rate for multiple reasons. One being blinds battery use, but the most urgent one: polling causes writes to the wifi bridge flash memory. This wears out the flash (it is not designed to withstand frequent writes). So polling could cause bridge malfunction. That is why I did not implements polling more often.
The fact that the official Motion app works is due to the fact that it uses an different way of communication, not available to integration developers.
