That (plus the logs) tells me there is a PHP configuration mismatch between what your existing sites have and what your brand new sites are getting.
On an old site, can you try:
- Starting the site
- Switching the PHP version to a new value (doesn’t matter, as long as it isn’t the current version)
- Click “Apply” next to the PHP version, and “Apply changes” when the modal pops up
- When the processes finishes, repeat this and switch it back to the original value
This is a shortcut to forcing the PHP config to refetch itself from the global configuration new sites are using. Does this clear up the 502 for the site?
@benselby I’d be interested in seeing if this is the same fix for you. Is yours also only existing sites, while new sites function as expected?