UK GB Machin Issued & Withdrawn Phos. Problems

HI

The attached stamps are being offered as

GB MACHIN CYL BLOCKS Issued & withdrawn Phos. Problems.

Can someone provide more detail ? When have they been issued and what was the exact problem should they have been withdrawn, and if so when ?

Thank you

Would be helpful to see the full text of the item offered... if any. It has been known for this type of stamp to be issued with "all over" phosphor in error. Issued as normal as it did not affect the sorting processes. The "withdrawn" part may refer to the later withdrawal of the stamp due to color changes or printer changes etc... but the entire stock would be withdrawn and not just the "error" ones.

Scotzm It's so easy to find

http://m.ebay.com/itm/GB-MACHIN-CYL...57Ciid%253A1


Why not simply ask the seller

I did ask the seller, but he told me he could not give me any more information than what is provided in the auction. He apparently had the info from the description of the stamps in a collection.