Not understanding how these filter/strainers work seems to be an easy mistake to make it would seem - expecting a basket to collect debris in a conventional way, so that you can observe its contents and assess what detritus is moving through the oil ways.
A mistake so easy to make that Norton (old’n’new) have been making it for many years apparently - with the vast majority of 961’s currently sporting this filter upside down

!
First time this incorrectly fitted assembly has been pointed out as such, despite the many (many) conversations we’ve had about it on this forum!
I’ll check the contents of mine next service and if it’s completely empty eliminate it as advised