This has happened to me three times now over the last couple of weeks. Seamus will get knocked down to zero HP. Instead of the Bleeding script kicking in, however, he gets sent straight to the DP. Each time it has happened has been in a biggish fight, or a laggy situation. Also, each time it happens I get this message:

I have no idea what's going on, but I do notice that his "got killed by" notification appears well after things have already started to drop on the death corpse. Maybe it's a lagg issue, maybe the boots really do have something to do with it?
Is it possible that the extra HP from the boot's Con bonus are going away when he hits 0hp and this is causing him to go past -10?