I have rerecorded programs that will not delete. The young & the Restless all episodes, suits 2 episodes, Doubt 2 episodes, My cat from He!!, & Nashville.
There are a few things you can try:
1. try rebooting the boxes
2. perform system refresh
3. Sync DVR
4. try deleting the recordings from the cloud(I once deleted a recording from the cloud & it also deleted from the box)
5. If steps 1-4 fail, open a support ticket for the engineers to examine because it can also be a backend issue which they need to fix.
6. If step 5 fails, swap the box. Possible equipment failure.