We're having an odd problem with saving tags on SearchKit saved searches that I cannot replicate on dmaster. If you try to save a search with changes to the search itself or to only the tags, it works fine. If you change the search and change the tags, the tag changes are not saved and in fact all tags are removed from the search - which is a real pain! The save button just says saving indefinitely, though the changes to the search are saved (except the tags).
When this happens, I note a console error:
POST [Our site]/civicrm/ajax/api4 503 (Service Unavailable), followed by a
Possibly unhandled rejection: undefined. But it is unclear to me why
[Our site]/civicrm/ajax/api4 would be called (as opposed to
[Our site]/civicrm/ajax/api4/entity/). This URL does in fact return a 503 on our site and returns
Could not find valid value for calls on dmaster (where this problem does not occur).
This is on 5.56.2 on D7, but it has been occurring since at least 5.49.