we occasional see this. make sure the drawing has finished redarwing all of the views and taht none are set to "draft" quality before you save it and check it in.
We have seen the same issue for quite a few releases of EPDM. What we have found is that it is the way SW and EPDM interact when checking in files directly from SW that causes the views to disappear. The workaround we use is to perform a complete rebuild in SW (Ctrl-Q) and make sure all the views are done updating - no more hour glasses, for multiple sheet drawings re-open each sheet after the rebuild, save the file in SW, close the drawing in SW and then check in from a EPDM explorer or search window instead of directly from SW.
It's not a fix, but this workaround has worked for us.
Performing control Q on all sheets and checking in resolved the issue. Thanks all!