When you talk to a Bivouc Administrator, he'll tell you the progress/durability glitch of the previous bivouac (or at least, uses the number of the previous bivouac).
This glitch can even be seen on the Version Update screenshots on this very forum!
http://forum.square-enix.com/ffxi/threads/35228 under Event Related.
Notice how #4 admin is talking about #3 bivouac, and #1 admin is talking about # bivouac?
:p