Dispatching private builds immediately (https://code.launchpad.net/~cjwatson/launchpad/build-private-bpb-immediately/+merge/345104 and its prerequisite) might help in this case, although only by chance. While the linux-signed build would initially be dispatched earlier, it would immediately dep-wait because the main linux packages wouldn't have been published yet. buildd-retry-depwait would retry it once the linux packages had been published, but that currently runs hourly, so it would have a reasonable chance of ending up in a good place.
This wouldn't be a proper fix, of course, but I think it would reduce the practical impact.
Dispatching private builds immediately (https:/ /code.launchpad .net/~cjwatson/ launchpad/ build-private- bpb-immediately /+merge/ 345104 and its prerequisite) might help in this case, although only by chance. While the linux-signed build would initially be dispatched earlier, it would immediately dep-wait because the main linux packages wouldn't have been published yet. buildd- retry-depwait would retry it once the linux packages had been published, but that currently runs hourly, so it would have a reasonable chance of ending up in a good place.
This wouldn't be a proper fix, of course, but I think it would reduce the practical impact.