Since a short while ago, I can no longer see timestamps on comments. Is this some new feature, or has something gone wrong with my ad blocker?

For instance, when I visit [this post](https://meta.stackexchange.com/a/306450/184981), I see this:

![](https://i.stack.imgur.com/rZNGW.png)

Note: since today, it looks OK at first, but the above issue occurs after a delay of 1 minute, when the system tries to update the timestamps.

This is with Firefox 52 (the ESR version, which comes standard with many Linux distros). The problem does not come up in Firefox 60.

Another problem is that the comments aren't visible at all in Chrome 57. (Again, the version that comes with my Linux distro.) Things are fine in Chrome 66.