When reloading any datapack (for an example, the blank one I've attached below), the following error is returned:

Non [a-z0-9/._-] character in path

I'm unsure of whether this bug relates to the .DS_store bug (MC-121380), as the world loading process gets stuck on the 'Loading world' stage in this case as well.
I decided to report it here just in case it was something more.

Attached files include the output log and chat errors, as well as a zipped version of the datapack I'm using.

Update/Edit:
In the 17w47b update, the output log confirms that this is a direct result of the .DS_store bug (MC-121380), giving the error:

Non [a-z0-9/._-] character in path of location: <namespace>:loot_tables/.DS_Store

and similar error messages for other subfolders.

Even so, I would like to point out that the path itself is legitimate, with only [a-z0-9/._-] characters appearing.