Curiously the cracks appear after the included warranty expires -- at least in the US where they only need to work for a year.
On Reddit, a user by the name of Snoo_23916, shared their experiences on the /r/GalaxyFold subreddit, where they opened the screen to show a friend their phone and heard a cracking sound. After this, the right hand side of the screen no longer responds to touch at all. Unusually, they also report that the phone was only opened 2-3 times per week over a period of 15 months, so excessive wear doesn't appear to be the culprit.
Another user by the name of Mizderrung complained that a three month old version of the phone cracked and Samsung refused to pay up claiming that there was an impact point and that they have to pay $700 AUD for a repair.