We maintain a set of billing tags on our AWS resources that are prefixed with "cost.". The 7.16.2 version of functionbeat errors out on those tags, despite me quoting the tag strings in the yaml file, it interprets them as objects and errors out when I try to update:
Function: functionbeat-cloudwatch-elk, could not update, error: can not convert 'object' into 'string' accessing 'functionbeat.provider.aws.functions.0.tags.cost' (source:'config.yml')
I was pretty sure that worked with the previous version I used (7.15.0) but I can't reproduce that behaviour now, so I probably hallucinated it 
Nevertheless, it would be good if I could set tags in formats that are completely acceptable to AWS. Do I need to do a magic thing to make it accept "cost.foobar" as a valid tag name, or is this a bug in the config parser?