Ok, so after some more testing, the issue ended up getting weirder. We started getting back HTTP 401 status for same calls that 10 minutes before that returned 204 No Content (so ok ad should play). This was going on the whole day yesterday, and the issue seems to have resolved itself on it’s own.
Today, all of the HTTP responses we get are 204, so technically it should be working fine, but only about 2 people see the ad. I even tested it myself to make sure it wasn’t just people using AdBlock, and both as logged out and my bot account (since I have turbo on my main) I saw no ad play, even though the API responded with the expected 204.