The problem with importing expired objects (media) is that catalogs won't be imported. Even worse when importing B2D media, they may get deleted again when no protection is set before the daily maintenance is running. Also be aware that only the initial protection will be saved on the media. When protection is reset afterwards from GUI or CLI, this is recorded in the IDB, but not on the media. This means that at import time, only the initial protection will be seen and not the one that may have been set afterwards. So if the initial protection has expired then the objects will be imported without protection, even when the protection had been reset earlier before the media were exported. A related article about this is:

Support Tip: Set protection explicitly for replicated objects

To resolve any issues of importing expired objects, the following environment parameter can be used:

# OB2_IMPORT_OPTIONS = -protect {none | weeks n | days n | until Date | permanent | extend} [-expired_only]
# Default: no default value
# This variable can be used to force a new protection period to be applied to imported media. It must be set
# in the Cell Manager's omnirc file. The optional "-expired_only" parameter applies the given protection only to
# media that are already expired at the time of import.
# Example: OB2_IMPORT_OPTIONS=-protect weeks 30
# The above value will force 30 weeks of protection to be applied to imported media.

You may be interested to some of my other Support Tips too: Support Tips listed per category.