OK we found the source of the error @<1523701070390366208:profile|CostlyOstrich36> :

It's quite strange. Apparently, using the string "ON" as a key in the PipelineController's config, and connecting it via

pipeline.connect_configuration(config)

results in that key being processed as a boolean. so for example if we define

config = {
"ON": False,
"param1": True,
...
}

we end with that config defined inside the pipeline object like so

{
True: False,
"param1": True,
...
}

resulting in the error downstream