429 Rate Limit Errors

I'm getting 429 errors fairly often on my mock API, despite not hitting it on a regular basis. This seems to be related to an HTTP/2 stream error, as here's the verbose output:

* Connection state changed (MAX_CONCURRENT_STREAMS updated)!

< HTTP/2 429 

< date: Thu, 26 Apr 2018 18:21:28 GMT

< content-type: application/json; charset=ISO-8859-1

< server: Jetty(6.1.26)

< 

* Connection #0 to host virtserver.swaggerhub.com left intact

{"error":"Exceeded rate limit"}

Are everyone's mock servers going through the same HTTP/2 endpoint?

Also, FYI, the charset of the application/json is invalid there. Not only is ISO-8859-1 an invalid encoding for JSON, but the standard doesn't even define charset as an accepted parameter, so it shouldn't be included at all. All JSON is supposed to be UTF-8, or some other UTF, which means no charset is needed.