I myself found the same problem and no longer use "reclamation".

I use a script that I developed that figures out which tapes are above my
(reclaimable) threshold and issues "Move Data XXXXXX" commands in non peak
hours on a daily basis.

To avoid processing tapes that I just sent offsite (PTF #1) I only process
the ones that have not been written to in 10 days.

You don't even need to recall your "troublesome" volumes, ADSM knows where
the file is in the primary storage pool and will re-create the offsite tape
in a new or appended tape.

I can send you the script if you want?