Samsung will soon launch the Galaxy S10 5G in the US, but the phone is already available in Korea, from the nation’s top three carriers. However, no matter how great the Galaxy S10 phones look, the Galaxy S10 5G experience isn’t perfect, according to complaints from early adopters. That’s because the phone is having trouble hanging on to 5G connections, and is failing to connect altogether when trying to fall back to 4G LTE.

A report from Business Korea says that Galaxy S10 5G users are complaining about data issues, but the carriers and Samsung claim that there isn’t much they can do to resolve the problem.

Users took to social media to complain that data service gets disconnected when the phone switches from 5G to 4G. Multiple reboots are required to connect to the 5G network again once the phone fails initially. The handover between 4G and 5G should be seamless and undetectable to the user, but that’s not happening.

“It is normal that smartphones switch between 5G and 4G naturally so that users can not notice it, just as they do not feel any delay and buffering phenomena when switching between 3G and 4G,” reports Business Korea. “The Galaxy S10 5G is loaded with one 4G antenna and one 5G antenna for the simultaneous reception of 4G signals where 5G telecommunication was not available. This is a separate issue from the fact that a 5G signal is not caught in the first place or 5G speed is slow for a smartphone due to the limitations of 5G coverage.”

Consumer complaints are apparently mounting, but the carriers and Samsung “are shirking their responsibilities and failing to offer proper countermeasures,” the report says. Samsung updated the phone’s software, and that’s all it could do, apparently. The carriers, meanwhile, finished updating their base station software, and some told Business Korea there were no more complaints after the update.

An unnamed industry expert explains that the problem isn’t the number of 5G base stations, but that the carriers have not optimized their networks to handle the switch between 4G and 5G seamlessly.

Verizon is expected to launch the phone in the US next month, at which point we’ll surely find out whether Verizon’s 5G network is any better with the Galaxy S10 5G, or if similar issues arise.