Enemy level scaling after sitcking around in one spot

[MJako]

I wanted to farm some sola toroid and so I head into the orb vallis, without taking a bounty, directly to the tempel of profit. After like 15 mins I noticed that the enemies are around level 70-80, but it was managable. After 25 mins I was struggling staying alive and at around 30 mins I had to bail out because of enemies level 115 one shotting me. The alert level was maxed (visually), but it felt like it kept on growing. 

I just want to know if any1 else noticed that and if this is intentional or not, because I cant remember anything like that on the plains of eidolon (and yes, I know that there was no global alert level on the plains).