Topology updates and relay restarts

The topology updater runs after relay restarts which occurs by default after 24 hours. I am wondering what happens to your core node during the relay restart. What if the restart happened while the core node was in the middle of producing a block or (just before or just after) would this interfere with the block production? My core node has only 1 in and 1 out so I’d imaging that this would be a problem. Is this why it is a good idea to have more than one Relay?