User Permissions Bug or not?

I don not know if this is any bug or not but I am going to ask just to be sure.
Yesterday I was testing permission level and I wanted to show 1 User, 1 Customer.
All I did was this:

  1. Created new user name Test Rob.
  2. Created new Role named CustomerTEST2
  3. I assigned CustomerTEST2 to the created user, Test Rob. (ONLY THIS PERMISSION. Not any other permission)
  4. Created new Customer named, Test Rob (The same name)
  5. Next, I set User Permissions to this User.
  6. On Role Permission Manager I add Customer to CustomerTEST2 and check “Apply User Permissions”.

Yesterday it returned only “Test Rob” customer. Only 1. Today it returns all the Customers.