You can thank Google for this.
In 4.4, they blocked write access to "real" microSd cards "for security reasons".
When they re-enabled it in 5.0, they invented a whole new way to access the files (whereas before, it worked via File functions, you know, "C:" was your internal memory, and "D:" was the microSd, metaphorically...)
And I just can't seem to bring myself up to work on this, given the required all-new-all-different code paths.
They just screwed it up for everyone (users, developers) for no good reason.