Hey there @Tahmid-Ali_99! As @azullFR has kindly stated, the issue with missing fabric is once again under investigation. @Ubi-WheelyDuck was correct in stating that an issue whereby fabric could not be looted was previously fixed, however unfortunately due to a more recent issue with looting small chests, fabric has once again become difficult to obtain. I'm pleased to say that a fix for this issue is scheduled for a future update however, so we'll be keeping everyone updated with regard to this issue over in the dedicated megathread!
I'll lock this thread now as it is a duplicate discussion, but please don't hesitate to report your experience of the issue over in the megathread if needed, or if wanting an update! Thanks!