nas326: Folder properties do not match

Hello!
For some time now, the NAS has been giving me the following problem:
if I ask for the properties of the folders, they do not match. If there are 11 files inside a folder, it tells me that there are 22! Also, when I copy folders from an external disk to the NAS, many files are written with length=0 when in reality this is not the case.
Do you think these inconveniences can be remedied or the NAS is broken and I have to replace it with a new one. Thanks to anyone who can help me.
(Translated into English with Google Translate)