It’s starting to feel like Apple’s tradition: every big launch comes with a problem. The iPhone 4 had signal issues when held a certain way, the iPhone 6 Plus was bending in people’s pockets, and the iPhone 15 Pro was getting unusually hot until an iOS update helped fix it.Now it’s the iPhone Duo’s turn. Just hours after sales kicked off, reports of screens cracking along the fold started coming in, though Apple says only a small number of devices are affected and has advised customers to contact AppleCare for a replacement.Apple shares slipped around 1% on the news, not a huge move, but could this turn into a bigger problem?In similar cases, Apple shares have typically dipped 3–5% over a few days, without driving customers away. Most users have stayed loyal, waiting for fixes rather than switching brands, while Wall Street has quickly moved on, knowing Apple has plenty of cash to cover repairs and legal costs.It’s also worth noting that the iPhone Duo was never expected to be a game-changer for Apple’s revenue. Gene Munster, managing partner at Deepwater Asset Management, expects Apple to sell 20 million units in fiscal 2027, accounting for roughly 7% of total iPhone sales that year.But there’s another risk that could hit Apple: AI.Rising financing costs, power shortages for data centers, intensifying competition between AI models, and doubts over whether massive investments will pay off have investors demanding proof that all this spending is actually driving revenue and profits.That puts the spotlight on Big Tech earnings and how quickly AI investments translate into real revenue. Investors want to see AI spending drive sustainable revenue growth, not just larger capital budgets, and so far, few companies have convincingly demonstrated they can do so.In particular, according to Apollo, revenue per employee in the tech sector has climbed from around $550,000 in 2022 to nearly $800,000, while the other 493 S&P 500 companies remain at roughly $550,000. Tech profit margins have also risen, while those of other companies have hovered around 10%.The bigger question is whether AI can eventually deliver similar productivity and profit gains across the rest of the economy. If it can’t, investors may start questioning whether the massive spending is really paying off, and that could put further pressure on tech stocks, including Apple.Keep an eye on the stock heatmap to see how Apple’s sell-off compares with broader market moves and whether weakness is spreading across major tech stocks. S&P 500 futurescan also offer an early signal of how investors are positioning ahead of the next market session, especially as Big Tech earnings and AI spending remain in focus. This article was written by IL Contributors at investinglive.com.