There can be many reasons for experiencing 502 errors, but if you run into a 502 when making a call to Freshservice PATCH /incidents/{id} and not when making other GET calls the issue is likely in your payload. In Freshservice all fields are permitted for update EXCEPT:

• description
• description_html 

Therefore, be sure to exclude these fields from the request body when you perform PATCH calls to this endpoint.

If you attempt to PATCH /incidents/{id} with an updated 'description' value a 502 will be returned with a provider message containing a very lengthy HTML body that does not explain the cause for the error and culminates in this message:

<h2>We're sorry, but something went wrong.</h2>
<p>We've been notified about this issue and we'll take a look at it shortly.</p>