Using numpy memmap to map a file on a remote server results in invalid argument crash

Question

I am trying to use memmap to get data from some binary files. Sometimes these files are located on a Dropbox server and not synced locally when they are first opened. Previously when this was the case, the call to memmap would cause them to sync and load fine. Very slow, but it worked eventually. Since I updated numpy, it now instead crashes, with an "Invalid argument" error and the file path associated to the file I am targeting. Any idea why this is the case, and is there is anything I can do to cause it to use the old behavior?

I gather from a few related questions that sync issues with Dropbox servers are common. Is it just a "not my problem" problem that I need to work around?