I don't believe that this time i saw that the fee drop to 20 sat per byte. I thought that its bug but i tried to test sending few bitcoin few hours ago and my fee is too low, I paid almost 18sat/byte check my transaction here
https://blockchain.info/tx/224f6d675f2062319daf896537bad6519eedaf26ab2e4b0b0f62453408b7a103
And my transaction was confirm in few minutes i think 15 minutes or around 30 minutes.

What do you think could be the reason is it because of lightning network or it is because of low transaction traffic?
Or there are lots of people are mining bitcoin?