The pre-check button submits a build of a change without a patch set number

See for example this change.

The first two pre-checks are triggered on patchset 1 and 2 respectively. But they both miss the patchset version.

A change without patchset just means "latest patchset". This can be true the moment of the build submission, but false later. It makes it hard to relate Coin tasks to specific patchsets.