I am doing exactly as said in the docs: sending instant 200 responses after receiving commands. Exactly as @rcoup is saying in How to avoid slack command timeout error?.
And it works perfectly on slack desktop. No error messages at all. However, when I invoke the commands on slack for iOS, these 503 timeout messages keep showing up. Weirdly, sometimes they show up AFTER the response is already there. :/
Is there any different time limit or nay different approach for mobile? Couldn't find anything within their docs.