Have you ever noticed that your I2P router has less peers after a restart?
https://i2pforum.net/viewtopic.php?p=3301&sid=7a0c77f87ec4bcfb86d7abd7b41a030b#p3301
I2P routers confirm the status of router infos when they restart. This means checking in to make sure they are still available and getting rid of those that are not. The amount of peer connections you see will vary until this process is complete.