Hi @Xavier_Pinto,
What is your re-scan interval configured for that storage location? You can manually set a shorter rescan period in Settings -> Storage -> 3-dot dropdown menu -> Edit -> Automatic Rescan Interval, does that help with this issue?
I should mention that NAS watched locations are a bit trickier, since they do not always report file changes to Roon in real-time. More information regarding this behavior can be found here but I am hoping that the automatic rescan interval will help.