Markets across Asia tumbled, with Hong Kong off almost 2 per cent, while Shanghai, Singapore, Seoul, Wellington, Taipei, Mumbai, Bangkok and Jakarta also retreated.Shares in Hanwha dropped more than 5 per cent in Seoul.The selling also came amid growing concerns that the AI-fuelled rally in stocks this year – which has helped push several markets and companies to record highs- may have been overdone and a bubble is forming.”Given the recent rally, positioning was stretched (and) any bad news is a cue to sell risk … which indicates the market is looking for an excuse for a selloff,” said Neil…