mklink directory junctions are inaccessible on Windows 10

I created a junction with the mklink command on Windows 7 and it worked great for the past 2 years. (EDIT: I have now verified that this exact scenario/problem still exists on a brand new laptop with Windows 10). I made a folder from my SSD drive (F:) available to my HDD (D:). Example:

mklink /J "D:\TestFolder" "F:\SourceFolder"

(Windows is installed on C:, both C: and F: are partitions on the SSD). Yesterday I updated to Windows 10 and noticed almost immediately that this junction was no longer working properly. The "shortcut" is still visible in Explorer and can be opened and its files/subfolders are visible, but not accessible (read/write). If I try to open any subfolder in the junction (D:\TestFolder) I receive the error:

D:\TestFolder is not accessible. The system cannot move the file to a different disk drive.

If I try to create a file in the junction folder (D:\TestFolder):

An unexpected error is keeping you from creating the file. If you continue to receive this error, you can use the error code to search for help with this problem. Error 0x8000FFFF: Catastrophic failure

If I try to rename/delete a file in the junction folder (D:\TestFolder):

Invalid device.

I have tried editing the security settings to give admin/users access, but none of the solutions online seem to be working for me (though I have seen similar problems posted by others). Basically I have the ability to view the files from Explorer in the junction folder (D:\TestFolder), but no read/write access. Accessing the directory from F:\SourceFolder still works fine, and everything worked fine on Windows 7 previously. Any ideas?