I have seen this same error sending collection parts and also the full collection item, prior to this you could send 12-14 collection items with no issue, then you could refresh and then send the same amount again etc etc.

However now the error seems to be generated at different intervals ie not 12-14 but can be the first, second, third etc.

Please resolve this issue ASAP as losing such valuable items when your trying to send them to an ally, clan member etc is most frustrating.