Yes, when loading a workspace that contains an experiment path, the client doesn't wait for the experiment to finish loading before launching the Python bridge or any other plugin window. I don't think this issue has come up before, which is surprising.
I will work on fixing this. In the meantime, you may be able to avoid the issue by adding a short wait at the start of your Python bridge script -- maybe a second or two, depending on how long your experiment takes to load.
I'm looking at this now, and I'm having trouble understanding where this is causing problems for you. Can you tell me exactly how the script's initialization fails? Is it expecting a particular value for a variable and not seeing it?