The cap has LPL engraving the tank itself has no marking except at the bottom it says made in Japan. LPL is japan I guess at least that is what I found on the internet. Brushing direction, the surface texture is identical I think they are of same set.
But I will keep that in mind, may be they are of different brand.
I have found that mixed lids and tanks leak if you can get them together. I think it is just oxidation on the surfaces which are your tank's problem. clean and lube should do it. If not, try the suggestions I made, if they are for you at all practicable.