Currently, the bridge starts new RPA jobs in the first environment returned by the UIPath API. Depending on how the result is sorted we might always choose the same environment.

We could either introduce load balancing in the bridge, which might need some sort of persistence
or we could make the environment configurable per External Task (e.g. by extension property).

Alternative approach:
Use queue mechanisms of RPA vendors, if supported. In UiPath, you can add items to specific queues instead of starting jobs directly. The orchestration then takes care of balancing the load. We could make this configurable as well either in the bridge or per RPA task via extension properties.