You can access the BacnetIP devices thru Struxureware and bind values to them. Subnets show and points can be uploaded but subnet devices dont stay online. Seems to be slow MSTP bus issues.
I think you are saying there’s problems with the response time of MSTP devices on a subnet, when accessing them over the main Lan. We can have a look into that if that’s what’s this is about. A wireshark capture on the lan would be a good place to get started, then we may need to do another for the RS485 but start with the Lan capture if you could.