Hi,
although I don’t have this kind of RDTA either, regarding mesh, my first idea would also be that the cotton is loose/insufficient under the mesh, it’s not evenly tensioned everywhere against it. But you write that the mesh sheet doesn’t heat up evenly even during firing, I think this might be more of a contact problem, perhaps Gilbert’s ideas might work (thorough disassembly, rinsing, cleaning, and/or the mesh sheet being clamped in parallel).
I found a thread about chain vaping dry hits (liquid supply issue), I’ll leave it here as an interesting find
“the one end of each SS rope rods IIRC were welded on the ends. I installed my SS rope rods with the welded ends into the tank section. The other (not welded ends) were what was touching the cotton wick.”
“If I remember correctly, one end of each stainless steel rope rod was welded. I installed the stainless steel rope rods with the welded ends into the tank section. The other (unwelded) ends were touching the cotton wick.”