I have two good acquaintances who are K-Market and K-Supermarket merchants, and indeed, taking sick leave seems to be a big problem for them, especially in the small K-Market.
Of course, no one can know if there’s a valid reason for continuous sick leaves, but when sick leave days start approaching 50 per year and often for different reasons, it certainly raises some concern. However, the work is fundamentally “easy” and not particularly physical, so that’s unlikely to be the issue.
This is, of course, just a small sample from my own close circle, and not directly related to this case, but since K-Markets are merchant-led, the merchant themselves usually has to cover these sick leaves, even if they’ve already worked 60 hours at the store earlier in the week.