The staleness check is basically: If the latest profile is more than 14 days old AND 7 builds away, then fail.

For example, if latest profile is generated with chrome RXX-1000.0.0 and current chrome version is 1006.0.0, it is considered OK.

This only works on master but not branches. Branches has chrome versions look like RXX-1000.100.0, which can be much older than RXX-1000.200.0. Their build distance is 0 according to current implementation.