Can't delete recordings with Cisco 435 multi room dvr and external hard drive

[CGDPA]

Started a month or so after I connected an external drive, however, the recordings that I cannot delete were recorded on the DVR, not the external drive. I've disconnected the external drive and reset the DVR (using menu), but the problem persists.

I see this has been reported by others for several years, but none of the suggestions has been a fix. Perhaps if others chimed in, the volume would attract Verizon's attention.