CPU number of cores seems not correct
Your CPU has only 2 cores, but supports 4 concurrent threads.
This is achieved by Intel's Hyper-Threading technology that allows to run two separate threads in parallel at the same time on one single core.
So 2 cores x 2 threads per core means 4 threads per CPU.
As you can see in the image you provided from Intel, the number of Threads is 4.
So I would say that Ubuntu is showing the number of Threads and not of the Cores