On my 6V '65, when I press in the clutch (via the pedal) with the engine OFF, it works fine... no weirdness or anything. Start the motor and as I depress the clutch it starts to whirr - then there is a "clunk" followed by normal clutch action. Sometimes it was FAR TIGHTER than it should be, and even when shifting between gears there was chatter - but often depressing it would loosen it to where it should have been with normal function..... after there is a clunking noise. Have been running the same clutch/pressure plate for about 6 or so years - daily driver, but not as many days this past year... got to telecommute quite a bit.
It started when I made a quick turn out of a parking lot into a road and the surface was a little damp and there were some pebbles, so the back end sort of powered around the corner with a little bit of additional slipage.
Replaced the front tranny brace a few years ago, but it looks at least like the central rubber is split up the middle.
The pressure plate I have has the central ring and a couple of "arms" reaching up from the edge to support the throw out bearings (with springs keeping the pressure on.)