Perth 2014 Post and Go date error

When the Royal Mail Post and Go machines went to the 85th Scottish Congress at Perth, another software error occurred on machine 3 resulting in the date showing as November instead of April.  

The receipts show the date as 11/11/2014 but more importantly the data string shows BNGB14 rather than B4GB14.  These were spotted on eBay and it seems that the error was soon corrected.  (See here, closing 4 June.)

As readers will know we didn't get any stock of the Perth Congress stamps.

UPDATE 20 May
Thanks to Joachim we can now show a scan with the last stamp with string BNGB14 (session 779; time 13:20:13) and the first stamp with string B4GB14 (session 780; time 13:25:39).