Time Machine always reporting wrong size after several full resets

Good afternoon,

I have been using Time Machine on a Macbook Pro 2012 backing up to a QNAP NAS TS-419 P II

After a year of using Time Machine without any issues I've now ran into a situation i do not seem able to resolve.

For several reasons I wanted to do a full Time Machine reset and do a new full back.

For that, after trying various solutions with no succes, I've deleted the sparse bundle, switched off Time Machine support, restarted the NAS, switched on Time Machine support again. Furthermore i did full reset on the Macbook following as per http://pondini.org/TM/A4.html

However every time I start a new backup Time Machine seems to limit the sparse bundle to 1.07 TB, while I have not set any file size restrictions. Next to that it's also reporting only 657 GB of the 1.07 TB is actually free. As if the old sparse bundle with the backups were still there.

Anyone who has been facing the same issue?

Thanks,

Gijs