Nether Sprouts do not break (like grass would) after its secondary block (Nylum) is broken
Block updating it does not remove it either, as if it is not supposed to break
I dont know if this is an error or intentional game design

The link below with time stamp shows me discovering this
https://www.youtube.com/watch?v=HH3EpucOjJo
Time Stamp: 5:32