babybuddy: Feeding via API returns 400

Hello,

I’m attempting to add a feeding via the API (though Bitfocus Companion). I got everything working for a diaper change, so I know the basic connection is correct. I am unable to get the feeding to work though. Does anyone see my error?

URL: https://url.tld/api/feedings/

JSON: { "child":"1", "method": "$(internal:custom_feedMethod)", "type": "$(internal:custom_feedType)", "amount": "$(internal:custom_feedQty)" }

Header: {"authorization": "Token abc123"}

Returns:
172.17.0.4 - - [16/Aug/2022:12:55:46 +0000] "POST /api/feedings/ HTTP/1.1" 400 71 "-" "-"

Thanks