webGUI not displaying file backup size

Hello, i’ve been using UrBackup for a good while and recently i’ve came across some strange bug on the webGUI. File backups do not display the size properly, instead of showing the real size, it’s displayed as “Used storage: Unknown” and “Size: -1 byte”, the logs do show the real size and there seems to be no relevant errors reported. Could someone explain to me how to fix this and why did this happened?