This bug is reported already and will be fixed in a future version I believe, you can look into this post if you want to Also a Workaround is for you to instead of having an editable of the device itself to have a creative_device and then inside the script to use it do
if(RealTestManager:=test_manager[TestManager]):
RealTestManager.MyFunctionHere()
You can do that ^ to avoid referencing the device directly till the bug is fixed. Hope you ahve a good evening.