I bought a Wingsung 699 recently from AliExpress because I wanted to try out a vacuum filler. Ink leaks from around the nib whenever I cap it, leading to ink getting on the grip. When I write, blobs of ink sometimes burp out onto the page. Is this typical for this brand? I have another no name Wingsung (I think it's actually a knockoff of the Hongdian dark forest) that has no issues.
Quality of knock-off brands like Jinhao and Wing Sung is going to be pretty universally shit. You can usually buy a handful and one will be at least decent though.
One thing you could check - any moisture present in the cap can tend to draw more moisture out of the pen. You could dry rinsing and then thoroughly drying (Q-tip, compressed air, whatever) the inside of the cap, dab the section and nib to make sure it's fully clean, let it dry for a bit (you can shield the nib from air with a cloth to keep it from fully drying out) and then try writing with it and capping it again to see if it sorts itself. If not it might just be way too wet and dumping ink in the cap, or you're knocking the pen around too much causing ink to leak from the feed. This is all of course assuming it's otherwise properly tuned.
Drying out the cap was a good call. I think reseating the nib was what did the trick, but thanks for the suggestion!