TDD on higher level components and no unit tests on lower level functions [on hold]

Is it normal for people practising TDD to find no need to write / duplicate tests for functions at the lower level, because they've written TDD tests on the higher level components? Because the TDD tests have covered the test cases for the lower level functions, you end up with no unit tests for the functions.

Is this normal for a proper TDD? Thanks.

Update: This was voted to be closed because it is more of an opinion-based question. While I agreed with that, can I please put forward the question to the experts out there to provide some guidance to the newbies?