Metadata not correctly shown on Kobo

[mv24]

I noticed that, after sending ebooks to my Kobo, information like tags and series are no longer updated. So, newly added ebooks don't appear in the right Series/Collection section as the "older" ones do. I'm aware that this is a two-step process, and I just occasionally send ebooks via Calibre to my device, so I think this issue arose a few months ago but I just noticed it. I use the KoboTouchExtended driver, without any problem so far.

I performed a quick search on this blog and other website and I've already tried everything. In the preferences, on the "Sending books to devices" page, I made sure the "Metadata management" option is set to the automatic option.
I also checked that the driver is actually configured to update the metadata, including the series. I flagged and activated every option about metadata update I managed to find across the "Preferences" display.

However nothing worked to solve the issue. Do any of you happen to know where I'm wrong or can give me any suggestion? I have about 1,000 ebooks on my device, and incomplete collections are driving me mad!

Thank you very much!