A little while ago I upgraded Samba from 3.14 to 4.1. I’m using Arch Linux on the client and server. This upgrade broke the ability for the client to access files containing colons, that is I could not read files with names like 2016-01-01 10:42.txt.
After much searching and messing around with configuration on the server and the client I found the fix is very simple. Just add nomapposix to your mount options on the client!