Safari 11.1

I don’t have any ideas, but this is also happening to me on 10.12.6, without Security Update 2018-002 (I’ve not installed it yet). I guess the ‘good’ news is that maybe the issue which I complained about and attributed to SendGrid/email tracking, is in fact a bug unrelated to the new link format in TidBITS emails:

So hopefully Apple will fix this bug, and previews from TidBITS emails will start working again, even with the new SendGrid links.