Samsung Electronics is retrieving all Galaxy Fold samples distributed to reviewers to investigate reports of broken screens.
It comes a day after the South Korean tech giant postponed the phone's launch.
The retrieval comes as the world's biggest smartphone maker met with embarrassment ahead of the foldable device's US release on April 26th.
A handful of technology journalists reported breaks, bulges and blinking screens after a day's use.
The company postponed the handset's launch for an unspecified period of time while it investigated the matter.
It said initial findings showed the issues could be associated with impact on exposed areas of the hinges.
A representative declined to comment further.
A person with direct knowledge of the supply chain said KH Vatec conducted an internal review of hinges used in the Galaxy Fold and found no defects.
The supplier declined to comment.
In March, Samsung released a video showing robots folding Galaxy Fold handsets 200,000 times for its durability test.
Samsung's head of IT and mobile communications, DJ Koh, has repeatedly said foldables are the future of smartphones.
Though the issue does not hurt Samsung's balance sheet, the postponement damages the firm's effort to showcase itself as an innovative first mover, not a fast follower, analysts said.
Samsung emailed pre-order customers upon delaying the launch, online outlets said on Twitter.
"Your pre-order guarantees your place in the queue for this innovative technology," Samsung said in the email.
"We'll update you with more specific shipping information in two weeks."