Apple Pencil not charging via Lightning cable

Recent purchase of 6th generation iPad and Pencil. I found that the Pencil will charge fine from the iPad, however, it will not charge using the adapter and Lightning cable. This was raised with Apple Support and I have had the Pencil replaced at the Apple Store. The new Pencil behaves the same!

I am using the supplied adapter (the right way round) and cable that came with the Pencil.

The charging Widget shows that the Pencil is connecting to a power source, but the charge level does not advance.

I have tried various USB sources but found no difference (Apple, wall socket, PC).