Wireless Xi box - DVR recording conflicts

A few months back I switched out our two Xfinity TV boxes for two wireless Xi boxes.  Now I am finding I have multiple 'recording conflict' issues when scheduling recordings.  I generally am scheduling less than 3 shows at a time, and my usage is only at 15%.  Is this an issue with the wireless boxes?  Do I need to have a 'regular' TV box and one wireless box?  Any suggestions are appreciated.  Thank you