Hi all! I just thought I'd give you a tip on how to get around this issue as we also came across the same problem when working on a project.
We're using 3ds max 2016 which now supports the Alembic format.
To get around the issue of the frames not rendering, we exported the realflow mesh loader object to Alembic. This way we only had to re-import the exported Alembic file and the Realflow Loader plug-in is no longer needed :)