Samsung is reportedly issuing replacements for faulty units of the bestselling Galaxy S3 following numerous complaints that the bestselling smartphone was experiencing 'dying out' episodes some months after owners' initial use.

Reports by Android Authority indicated that the Samsung phone is "turning off and not rebooting without any explicable reason."

Complaints have flooded forums in XDA Developers and Reddit, which reportedly attracted hundreds of users more than a month ago, all of them expressing bewilderment on the mysterious Galaxy S3 'event'.

In XDA forum, S3 owners reported of phone "mainboards (that) suddenly died ... and the devices seem to last between 150 and 200 days before failing."

The 'bricking incidents' are attributed by XDA Developers forum posters to the Galaxy S3's NAND component, which reportedly "is becoming corrupted and failing."

And Samsung responded positively by deciding to contact affected S3 owners to offer replacements for the malfunctioning handsets without much fanfare, according to Android Authority.

"Samsung are replacing them under warranty whether or not people have rooted the devices or installed non-standard firmware," said the report.

However, forum users continue to voice out reservations, insisting that Samsung's replacements come with the same faulty phone mainboards, potentially leaving the new S3s "faulty in another 200 days," said BGR News in a report.

One Reddit user claimed that his communications with Samsung call centre and service personnel appear to indicate that the problems have been observed earlier by the tech firm's technical people, which should partly explained why the company readily agreed to offer replacements, Android Authority.

The new Galaxy S3 issue came barely a week after security vulnerability was cited on its Exynos-4 mobile processor, again cited by XDA forum members.

Shortly after the possible exploit was made public, Samsung acknowledged that existing architecture of the processor could be carrying likely holes that hackers can exploit via app-based malware attacks, BGR reported.

"Samsung has since said it will patch the hole as soon as possible," the tech site added on its report.

It remains unclear if the two Galaxy S3 hiccups are connected.