And I'm thinking it's the former 
On the statistics page, I'm seeing a sharp decline in "Certificates active" in the first graph with also a smaller decline in "FQDN Active" and even smaller yet for "Registered Domains active".
If we look at the Let's Encrypt Certificates Issued Per Day graph and zoom in on the last 2 weeks, certificate issuance seems to have halted according to the graph since about half way of October 15:
I'm guessing this isn't how the stats are supposed to look 