Ram consumption, as reported by task-manager does not seem excessive
ram consumed by Lightroom itself or the whole system?
I've been getting these last week when I was opening multiple Google Maps pages (with WebGL) in Chrome and from withing Lightroom. (I was checking gps coords accuracy in street view).
I have 8GB ram, Lightroom allocated about 2GB, each chrome page under 1 GB and total used RAM rasied to abnout 6.6 GB.
So, in my case it was Chrome that ate up the memory, but Windows reported Lightoom, perhaps because it was the process with max amount of RAM allocated.