You cannot pick the spawner block as you can do with other command-only accessible blocks (ex. command block, barrier, structure block etc.)
MC-154644
Cannot middle click on monster spawner to pick block in creative mode
Resolved
Duplicate
0
This is not a bug.Before 1.14, you can't take six sided logs.But after 1.14,you can take them.You can give feedback and they'll do it if it is neccesary.
https://aka.ms/javafeedback?ref=game
Have a good day.