ARD: Offline Status

We are using ARD for academic purposes. Almost at random macs seem to "fall out" of ARD. They show an offline status with no IP but are most definitely on.

Currently I've found that if you attempt to re-add the mac it will successfully re-add but now showing two identical computers, one online and one offline. The primary problem with this is with our scheduled tasks running once a week it means that the list of computers needs to be updated within each task while crossing our fingerings that another doesnt "fall out" before or during the process.

Note: we are using deepfreeze, and likewise (for joining windows domains)