When a bug is closed, the card is closed, and then the card is eventually moved to the archive. If the bug is later reopened, a new card is created, replacing the old one on the bug's whiteboard status. However, we maintain the previous assignee that was set on the bug, which is somewhat pointless, since so much time has passed that it doesn't matter.
So let's clear the assignee at the time of the new card creation.
When a bug is closed, the card is closed, and then the card is eventually moved to the archive. If the bug is later reopened, a new card is created, replacing the old one on the bug's whiteboard status. However, we maintain the previous assignee that was set on the bug, which is somewhat pointless, since so much time has passed that it doesn't matter.
So let's clear the assignee at the time of the new card creation.