problem on my end or someone leaking dhcp?

[Calderon]

Im on university network IP´s from range 91.X.X.X. I started having below message couple hours ago. dc0 is external and xl0 is my LAN (192.168.0.0/24)

Feb 23 12:55:21 bsdkone kernel: arp: 192.168.0.1 is on lo0 but got reply from 00:21:91:72:14:64 on dc0
Feb 23 12:55:36 bsdkone last message repeated 5 times
Feb 23 12:58:09 bsdkone last message repeated 16 times
Feb 23 12:59:26 bsdkone last message repeated 12 times
Feb 23 13:00:31 bsdkone kernel: dc0: promiscuous mode enabled
Feb 23 13:00:52 bsdkone kernel: arp: 192.168.0.1 is on lo0 but got reply from 00:21:91:72:14:64 on dc0
Feb 23 13:01:07 bsdkone last message repeated 5 times
Feb 23 13:01:46 bsdkone kernel: dc0: promiscuous mode disabled
Feb 23 13:01:55 bsdkone kernel: arp: 192.168.0.1 is on lo0 but got reply from 00:21:91:72:14:64 on dc0
Feb 23 13:02:04 bsdkone kernel: arp: 192.168.0.1 is on lo0 but got reply from 00:21:91:72:14:64 on dc0

So is this doing harm on me, is this somehow my fault (doubt it, because this started just hours ago, and i have been running this for months without problems) or someone leaking something to this network. How can i prevent this. Changin my LAN subnet maybe? or can i block this with PF?