Guys, story/question about Panasonic filters...

I have a friend who has this cheap, counter top Panasonic attached to his faucet. Last time I was at his place, tried his water and it had bad, medicine taste.

So I asked him if he changed cartridge ever, and he told me he did just recently. Ok, nevermind.

Then a customer writes to me, asking if our FD will be able to get rid of taste. We pinpoint the problem not to his water, but to... Panasonic filter.

Then I recall that few weeks ago we installed a filter to replace Panasonic. I did not pay attention back then, but now texted the customer. Reply was "the water did not taste well even with new cartridge".

At the same time, not everyone can taste it, but some people definitely can. Conclusion is, most probably the cartridge leaches something into water that gives that taste.... I did not expect this from Jap company, when filter does more harm than good...

Anyone else experienced that with their Panasonic?