Interesting to know people are backing up through the web interface. I always use SmartPSS, and that one does not have any issues with the new firmware.When running this version with NVR no Backup Option under Chrome or Firefox. Only IE.
Also, when backing up to .mp4 from IE I get audio but there is no video. This was with a IPC-HFW2831T-ZAS V2.800.0000000.2.R, Build Date: 2019-04-04. I was able to backup .dav and play using Smartplayer. Prior to this ugprade had no problems backing up to .mp4.