"...while modifying an existing 2017 ASE corridor, the corridor linework disappears for the current alignment. The only solution we have found is to delete a marker, export the corridor, then add the marker back in, export the corridor, and the corridor linework is back. Any suggestions?…"
You shouldn’t have had to replace any Design Markers, but I understand how frustrating is to be forced into working through software problems that interrupt your work-flow.
ASE Civil 2017 system defaults overly-suppressed the program’s sensitivity to design data changes that should trigger a refresh cycle of the design drawing objects (Corridors, Pads, Ties, Plan Labels, Basins). Refresh cycles are usually triggered after paving data has been shared. This is to support accurate synchronicity between the physical model and the virtual model. Similar issues have plagued other clients ever since ASE Civil 2017 was released. However, the latest service pack was updated in the hopes that this and other problems will be resolved.
If you download and install the latest ASE Civil service pack, hopefully problems like this should be the exception and not the rule, moving forward. On the other hand, if you are still having problems, please let us know.