Bootcamp the startup disk cannot be partiitoned
This is a very common question. Again, here is the commands you need to enter in a Terminal application window.

The next two commands will remove the disk1s4 partition labeled BOOTCAMP and the disk1s3 partition labeled OSXRESERVED 

sudo diskutil eraseVolume free none disk1s4
sudo diskutil eraseVolume free none disk1s3


The next command return the free space back to the disk1s2 APFS container partition.

sudo diskutil apfs resizeContainer disk1s2 0