It is strange, seeing as, on paper, your application seems quite strong.
I would note that, as I have heard it, Trinity is extremely competitive for STEM subjects, and particularly those pertaining to mathematics. Seeing as you have not been given an interview, it would appear that they do not consider you to be a realistic applicant (Cambridge's words, harsh as they may be). This is likely due to there being an extremely strong pool of applicants this year, meaning even strong people miss out on an interview.
Sorry ;(