Just kidding, there is no closure. I could not replicate this issue again after multiple reboots.
Linked original thread: https://lemmy.nz/post/1024414
Just wanted to say thanks to everyone for their suggestions, and easier to make a post here than reply to each single comment.
Ask the network admin about arp tables and caches. If it’s your router then upgrade firmware (or change the OS on it).
If it happens again I’ll try that