About 10 % of my queries are returned as Bad Gateway 502 errors (which will timeout after 10 minutes, very annoying).
This happened once I got close to the hard limit of budget that I set ($1k per month).
I increased the hard limit to $2.5k, but even one week later I still have the same issue with this account.
On another openai account where I was not close to the limit I'm not getting any of these errors, therefore I think its related to budget information not propagating correctly in all your systems.