This is likely not a bug!
To put it simply…
Games failed to respect rate limits so a large group of services now block requests from Roblox servers, or rate limit even more strictly
This is exactly why Roblox was blocked by Discord in the past.
For example, Trello now limits requests from Roblox servers to 10% of their normal rate limits. This is entirely at fault of users of these services on Roblox not following website guidelines properly, spamming requests and completely ignoring rate limits and response messages when they fail. A majority of services return response codes for when you need to slow down!
If Discord webhooks, or any other services blocking Roblox return again, it is a guarantee that if games continue to neglect to follow rate limits services will just immediately start blocking Roblox again.