Yes but no change the breather I got was 507-0646 cat# it didn’t have the push down to relief the air. But it had the same nipple to screw down on the tank. Parts book show a screen on the inside of the tank where the return line from the filter goes through the tank. Not sure if that screen could be plugged? Haven’t put a gauge on the sending unit either.
SIS does show the original breaker/breather 133-1963 changing over to the 507-0646.
Not saying the return line screen can not be the problem but the screen in the return lines for most systems have fairly large holes in them. Now I could see if someone had worked on the machine and stuffed a rag in a fitting or line to keep dirt out and forgot to remove it before hooking up hose there could be enough in the screen to cause back-pressure. Getting to the return line screens means splitting the tank so I would eliminate everything else first!
I still would recommend trying to test with an actual pressure gauge teed into the port the send er is mounted in just to know 100% sure you are seeing too much pressure there. Then I would be trying to move the pressure gauge from the inlet side of the filter to the outlet side of the filter. This will tell you if the pressure is high because of the filter or some problem in the tank.
One more idea/question what filter are you using on this machine? I see you mention it was the "correct" one from Cat but what is the actual part number on it? The more information the better chance of an answer.