Ah. Uh, sorry. I was just corrected on MCForum as well. That value is inputted as a string. Hadn't looked at it that way.
As of 1/7/2018, I get this quite frequently still. Today there have been 4 of us all on at various times, and we each get kicked occasionally all at the same time.
Dustin Cox, no. The more people that find the existing bug ticket, make a comment reporting as much information as they can IN ONE PLACE, and then maybe upvote the bug ticket, the better.
*edited to clarify
Can confirm, have this issue on my Realms server today. While mining I first noticed I was unable to pick up blocks. I assumed some network issue had reset my session or some such, so I restarted Minecraft. But I got the netty error while attempting to log in. My daughter also tried logging in, and she has the issue as well. I tried switching active worlds and got an error that simply read "504".
**update - came back online but reverted to a 30 minute old save, losing half an hour of mining.
There was no crash.