To the OP... do you have OTA connected? Hot, humid, & clear weather can create a situation in the atmosphere called "ducting" and OTA signals will become... well lack for a better term... weird. Check the pip sorce & make sure that it's on a sat signal & not an OTA channel... this should help...
It's a software bug that's been around a while, if the pip is tuned to a weak OTA the unit will give a LOS box when the OTA is out, even if watching Sat or DVR...