RIM (RIMM) is investigating the problem and says it appears to be specific to the Japanese market. “This issue appears to be specifically limited to the BlackBerry Bold devices sold in Japan since last week and sales of BlackBerry Bold devices in other countries are unaffected by this matter,” the company said in a statement.

Another tough break for the Bold, which has suffered quite a few of them since launch. Back in January U.K. carrier Orange was said to be considering pulling the device from its lineup because of persistent problems.

Interesting to hear that the Bold shares the iPhone’s erratic 3G connection because the device doesn’t share the same Infineon Technologies (IFX) chip believed to be the source of the iPhone’s troubles. Which means the only real point of commonality between the two phones is AT&T’s 3G network, which may still be a bit too immature for either of them.

The device is largely as expected–an iPhonish-looking thing with both GPS and Wi-Fi, 1GB of permanent flash memory, a 2-megapixel camera, full HTML browsing, 3G support on GSM networks with HSDPA access and, of course, the BlackBerry’s one-trick killer app: instant, secure email. That’s a compelling combination for business users and casual ones not easily swayed by the iPhone’s hype juggernaut as well. Indeed, Citigroup analyst Jim Suva says it could boost RIM’s quarterly shipments by 200,000 to 400,000.

But perhaps not without a bit of struggle. The BlackBerry Bold won’t ship until as late as August, which means Apple (AAPL) could beat it to market with the enterprise-friendly 3G iPhone it’s rumored to be uncrating at its Worldwide Developer’s Conference in June. Which has got to worry RIM. After all, the first-generation iPhone had claimed a 28% market share by the fourth quarter of 2007. That’s still less than the BlackBerry, which holds about a 41% market share, but the iPhone hasn’t even been on the market a year.