Drag and Drop PDF

When I drag and drop two PDFs from EagleFiler to Mac Mail the second one is always empty and shows as 0KB. Is that just me? Am on 10.11.6 so appreciate I am not completely up to date, but interested to know if upgrading will help or if it is an issue within EagleFiler

Cheers
Doug

This is caused by an OS bug in 10.11. Apple has the bug still listed as open, but at least on my Mac it seems to be fixed in 10.12.

Thanks Michael -updating to 10.12 did the trick.