When on the I brake I get a pulsating feedback on my rear brake lever. I checked to make sure the wheel is true, and also the dish, which is ok.I re-checked the torque on the caliper bolt and adjusted it to 9Nm. The tire also has no bumps that I can see or feel. Any ideas?
After the discussion in the comments, I suspect that the rim is deformed.
This can happen if you hit a pothole or kerb too hard, especially if the tires are not pumped up hard.
If the rim is deformed then you may be able to see patches where the brakes have worn the rim more. It's the brakes grabbing on these that create the feedback you are feeling.
There is not much to be done about it. Some people try to straighten them using a wooden mallet, but the success rate is low. Often the wheel is worse rather than better.
To avoid this kind of damage in future try to get your weight off the wheel as it hits the bump, by getting out of the saddle and moving back as the front wheel hits, then moving forward before the back wheel hits.
A rim worn down from age through braking may shudder. In my experience the rim shuddered more when the tyre was more highly inflated.
This can be tested by clamping the brakes on the bicycle, and turning the wheel to detect uneven deformation when the brakes grip excessively at particular points.
The deformation in this case will not be immediately obvious to touch or sight. After testing with the brakes, the deformation should appear as a spreading of the rim at the most worn section.
In this circumstance the rim will need to be replaced, involving rebuilding the wheel.