GPS Glitch and EKF Fail Safe

Hello All,
I am fairly new to ArduPilot so forgive my ignorance on any of the topics. I am flying a Aurelia X8 Octa copter with a Cube Blue installed running ArduPilot 4.1.5. I have been running some test flights out in the parking lot next to our office flying some short missions in Auto Mode. I have had success flying these missions without any issues but sometimes I run into an issue where I receive a lot of GPS glitches followed by EKF Lane switches and then ultimately EKF Fail safes which put the drone back into Alt Hold and I have to take control and land manually. I have been flying in the same location consistently with pretty much the exact same mission every time but the GPS glitches are inconsistent with when they happen. I have included two separate flight logs/missions where we have seen the problem a happen. I am not very savvy to deciphering the flight logs but it does seem obvious that I am having GPS issues but I am uncertain why this is occurring sometimes and not others.
Should i investigate getting a new GPS unit or could it just be due to metal around the parking lot interference?