Toilet or wall leak..don't know where from

We thought we were having a toilet leak as we had already replaced the wax ring and floor was still buckling. Bought a new toilet in January, took in out in July to replace the wax ring, some water residue.
Now we took it out again because noticed some futher buckling and returned the Jacuzzi toilet to Lowes.

We didn't feel water but decided to take out the hardwood in the half bath.
This is what we found. It looks like it's from around the toilet but can't tell if it's starting in the wall or not. It's completely dry, not damp or anything.
Could it have been an old leak (from the Jan. to July)?
Anyone's thoughts?
There is no buckling in the dining room which is on the other side of the wall and no signs of water on the walls or ceiling.

If I'm interpreting the photos correctly, the closet flange is still flush with the original floor, but you have added a new laminate layer. If so you need a spacer ring to bring it flush with the new layer. Otherwise you could have an intermittent leak through the wax ring.

How do I know...this happened to me a few months ago. Before I bought the place the previous homeowner added a tile layer but didn't add a spacer for the new floor level when they replaced the toilet. It didn't leak for nearly a year. Then I started noticing a bit of white mold on the bathroom ceiling below...I poked a finger through with just a light touch. Flush...drip. The wax ring on the toilet was just barely sealing it for the first year, but after I stood on the seat during some fan maintenance the tenuous seal must have broken in the back. The good news is that it was an easy fix. The ceiling damage? Not so much.

That's my guess anyway, but I'm not a plumber.