Interesting. I don’t reboot my node often, but when I do, I drop a lot of connections, and it takes many hours - days - to become as connected as before. This is normal.
I always get my 16 outbound connections quickly (8 random outbound by default for security, and I have a list of preferred additional connections which fill up the optional extra 8 outbound.) The inbound connections build up over time, as other nodes try to connect to me at random.
I noticed today after reboot that two of my first couple of inbound connections came in through Tor to my onion service address. See here:
The three .onion addresses are outbound connections (note the up arrows) from my .conf file.
The two inbound connections (note the down arrows) came in via my local Tor proxy (hence the 127.0.0.1 address.)
The rest of my 20 connections are through my public IP and over the clearnet - I run my node as a bridge between clearnet and onion network. (It will grow to 40 or 50 connections again, soon enough.)
It’s good to see this onion usage growing, because there are people in the world who rely on privacy to help protect them.