Stiff tonearm on VL12

I have a VL12 with a Concorde Club mk2 cartridge fitted. I’m using 3g of tracking force as recommended by Ortofon. When playing a record and the tonearm gets close to the centre of the platter, it often skips.

My first thought was anti-skate, which is set to 0. However, any setting other than 0 makes it worse and it skips more often as a result.

If I pick up the tonearm and move it back and forth, I can feel stiffness or tension in the arm as it gets closer to the centre. So it feels like it needs some lubricant or something to loosen it up.

Does anyone know if it is possible to lubricate the arm joint in some way?