Hello -
A part of the cloud build management infrastructure will be upgraded (various app patches and a full reboot) on Thursday night, February 23rd at 8PM Central US time, with the work expected to take up to 60 minutes.
During this time, Cloud Build will still operate normally, just with reduced build capacity. As a result, some build requests may queue temporarily during that window (depending on demand), but if that happens, those builds will proceed normally as soon as everything is back online.