Yes, it's probably just a case of this place is better than that place. If you collect your eggs every day one of them may get in her head that isn't a safe place to put the eggs because they keep disappearing!!!!
So she finds a more secure place where the eggs won't be stolen every day and then someone else sees her and thinks "WOW, what a great idea!" and bingo, they start laying in the grass.
I have had hens lay in some crazy places. We found one nest up and across the railroad tracks, through a Christmas tree field across a trail and in a bramble patch. My son was walking on the tracks when he noticed a chicken scurrying up through the woods. Took us forever to find the nest, but since it was full of green eggs we knew it was one of my chickens!!
I also had a hen jump in the hole in the back of the riding tractor that was the grass catcher. We had the attachment off, but the big catcher was left on and so she would jump in, at least a three foot drop and lay her egg in the mesh catch-bag. I still can't figure out how she got back out again. She did that for a LONG time!!!