Furby, could it have anything to do with your pipes or water supply, as in, I dunno, anything that could have made your local water supply harder or softer? That might affect the taste of tea, mightn't it? But then I suppose you'd have noticed a change apart from tea, so maybe that's not it 
Had managed to remain blissfully unaware of the celebrations popish until this thread 
- but now you mention it, it's surely his responsibility to ask all his sheeplets to celebrate quietly indoors! Bet he loves it, but convinces himself he's really only loving it because it's all to the greater glory of the Holy Figment 
Wondering if we should buy him a present - any ideas?
A plane ticket to Warsaw perhaps?
It would appear he is too lofty for tickets and such mundane items. He was flown in to an airforce base with plenty of fighter support.
Oops, sorry, I didn't mean to kidnap this thread. Heliophile's suggestion is good, to try a different source of water; perhaps distilled water might make a better cup. Local municipal changes to the water supply, chlorination, fluoridation, plus seasonal shifts in micro organisms and naturally occuring minerals, all can change the flavor of tap water.
Also, if you've had this latest respiratory virus, it appears to have a significant damaging effect on the taste buds. It may take you as much as a month for you to return to a normal sense of taste.
Likewise, if you have spring allergy symptoms, this can have quite a deleterious, albeit temporary, effect on the taste and smell senses.
I wish tapwater were distilled. Mine is so hard it's a case of "one lump or two" In fact I reckon you could pour it into a mould and let it settle and make your own house bricks. I'm always descaling everything it touches.
I do use it for tea as it happens, but have bottled water in hot weather for drinking
I do not know of any changes to the water supply, I certainly haven't been advised , but I suppose they don't bother with such things these days.
They have been building a lot of new buildings round here and it has been cut off quite a few times so perhaps they have. They have probably replaced all the old mains pipes with shiny plastic and I missing my daily fix of lead or something.
I sympathise with you looking at the popes mess. When he visited England in 1983 they closed the motorways to use as big car parks and the roads and even all the train stations in a 5 mile radius and wondered why not as many people turned up as hoped for. The people in the 5 mile radius were not happy as they were prisoners for the day.
The Popemobile is bulletproof and he is constantly surrounded by bodyguards. He presumably lacks the required faith in his God to protect him, or more likely, he realises that such 'faith' is all bullplop. After all, Pope Johnski Polski had complete faith but was still shot in an assassination attempt.