Oil cartridge becomes very difficult to hit, need to suck extremely hard to break the seal, anyone know what causes this?

Every time I get an oil cartridge, it hits well for a few days. Then all of a sudden some sort of seal forms. When I attempt to hit it, I have to suck really fucking hard to get the seal to break, then the seal will break and I will be able to hit it normally.

Does anyone know what causes this? Or how to fix it? It’s so annoying.

Only thing I can think is sometimes I unscrew the cartridge to charge my pen. It seems to occur after I have unscrewed the cartridge.