Yes I had issues too and looking at the new comments page [1], it seems there was an outage of sorts from around 16:00 to 16:40 UTC. Would be interesting to hear what happened, if any mod/admin wants to share.
EDIT: Seems like all the comments that were submitted during that timeframe are showing up now.
EDIT: Seems like all the comments that were submitted during that timeframe are showing up now.
[1] https://news.ycombinator.com/newcomments