Husqvarna LTX248XD with Kawasaki Engine - Downhill Stalling

[Hydestone]

My mower is losing power when going downhill, not sure what is causing the issue. It runs fine going uphill and on the flat, but when I am going downhill, the engine will suddenly lose power and sometimes stall out. When I start it back up, I usually get a puff of black smoke. I changed the oil, all good. Fuel is good too.

If I keep the accelerator pinned when going downhill, it doesn't seem to stall out. But if it's 90% down, it will stall. Also, if I go downhill without the blades engaged, it is less likely to stall. Here are some videos of the problem. In the downhill video, it starts to stall but recovers, then ultimately stalls.

Any thoughts on what is causing the issue?

Uphill:

Downhill:

 

[ILENGINE]

Almost acts like the fuel pickup tube in the tank isn't submerged when going downhill.

 

[Hydestone]

The tank was probably 90% full when I recorded that video. I was wondering if there was some stuff in the fuel line that blocked fuel intake when tilted down and slightly to the left, but the line is clean.