In our testing of Q2 2017, we have found an intermittent issue where students using Chrome are unable to use the Browse My Computer option multiple times to select files to upload to an Assignment. The first time you use the Browse My Computer option it always allows you to add a file to your assignment. However sometimes when using it a second time (say to select a second file) then the file is not successfully added to the list of files to be uploaded.
I made a screencast which illustrates it both working and then not working. It seems about 50/50 for us if it happens or not. Chrome file uploading issue Q2 2017 - YouTube
We are curious if anyone else has seen this and if this behaviour exists in Q4 2016 too, as we have not tested that.
There are workarounds in that you can ctrl-select to attach multiple files the first time you use the box, and the drag and drop feature still works to allow you to add multiple files.