This means the solenoids are hot or over heated. This may happen after a very long numbering job using excessive pressure on the impression control dials.
Turn the machine off and let solenoids cool down. This will also occur during a perf job when the heads are in a locked position and the numbering job hasn’t been cleared from memory. Unlock the heads and clear the numbering job. (GW6000 SN 2110 and lower)