Tholin is not one thing.
Tholin is a term used to describe a broad spectrum of molecules developed under vastly complex and hard to precisely duplicate conditions which are influenced by factors such as temperature, ratio of gasses, the state of those gasses (liquid, solid or gas), pressure (which changes the boiling point of gasses), quantity of UV light or charged particles and at what ratios.
Additionally, depending on the conditions that create tholins, some are gooey like tar while others are powdery, some are rusty red while others are brownish yellow. some develop on the surface of icy bodies while others are found in their atmosphere.
This image of Pluto's north pole is what one would expect to see when looking for the tell tale signs of Tholin. There is a layer of methane covering the surface in a bluish white snow.
Atop the methane snow is an orange/yellow looking material that is likely tholin. The surface methane is being exposed to UV light creating the light orange colored tholin.
Is tholin being produced in Pluto's atmosphere?
New Horizons turned around after it passed Pluto and took this picture illuminating Pluto's atmosphere by the light of the sun.
Pluto's atmosphere is blue.
I would think we would see some form of yellow or orange colored haze similar to Titan if the atmosphere was producing tholins.
Scientist suggest tholins are being produced in the atmosphere and they are simply bending the sun light at an angle that allows for a blue hue.
This is the North East section of Sputnik Planitia. There are two peaks or ice mountains protruding above the fluid, they appear to be connected to the land ice below and are being engulfed by the fluid.
We can see the fluid flowing around the mountains creating pockets or eddy's developed behind the obstacle as the nitrogen glacial fluid passes around the mountain peak.
In this scene where the fluid is moving around the stationary objects we see eddys on the side opposite to the fluids direction of travel.
The face of the mountains which is being hit by the fluid shows ripples as the fluid impacts and rebounds back.
This is the opposite of what is seen at Norgay Montes where the icebergs are the objects pressing into the land, hence the eddy at the non volcanoes at Wright Mons is on the opposite side of the blocking object as seen in this image.
In the above scene the icebergs are moving into the land so the eddy is forming opposite the direction of iceberg flow. The icebergs are acting like bulldozers pushing into a muddy berm.
In this view you can see the similarity of the icebergs on the right called Norgay Montes with the two other structures that are being swallowed by the folding mud like land.
Upper center is a very angular shaped object in the muddy ground covered in tholin. The surrounding terrain has folds indicating the land ice is flowing/folding around a sharp angled object.
This suggest this object is one of the icebergs laying on its side and getting swallowed by the soft muddy land.
Stuck in Muck
Here can be seen multiple sites with jagged edged icebergs demonstrating how the land ice has been softened by the nitrogen flow and is wrapping around the icebergs with rippled waves.
Something else that can be clearly seen in the above images is all the troughs of the rippled land ice are filled with tar like tholin. How does that happen? The tar like tholin floats atop the nitrogen flow accumulating around the edges where the land and the icebergs collide creating ripples in the land. This tar then fills the crevices.
We've seen this process on earth with the Exxon Valdez disaster in Alaska and the British Petroleum oil spill disaster in the Gulf of Mexico where millions of gallons of oil were released and floated on the ocean until it arrived at low lying land areas.
This is what is happening to the tar like tholin, its washing off the icebergs and floating into the rippled land areas created as the icebergs twist and torque the softened land.