Most likely, the service you mentioned closed some channels and lost connection to parts of the network.
I think the problem is much bigger and it's connected with Hetzner shutting down every nodes related with cryptocurrencies and that drop on chart is representing 10,000 Bitcoin Lightn.ng Nodes.
One member posted this information today on forum, and I can't be totally sure about this, but I remember hearing this news about Hetzner recently.
The hetzner blanket ban on crypto is taking further effect, in accordance to their terms of service. In the last 3 days, 10,000 bitcoin lightning network nodes were cut from the network. It is very likely that this is due to continued enforcement of Hetzner TOS upon its customers.
I don't think that's related at all. Again; those nodes are still reachable by every other network explorer; plus, Hetzner didn't have that many locations, servers and thus probably also Bitcoin / Lightning nodes, so far. They are only now starting to expand to America and elsewhere.
Also, that ToS update was months ago; late spring, early summer.
Just replied in the other thread but I have no issues connecting to BTC and LN nodes on Hetzner IP space so I don't think that is the issue.
Are there still reachable nodes in Hetzner's IP space? In that case, the ToS update seems hard to enforce, doesn't it..