Google PageSpeed Total Blocking Time issue

Hi,
I’m having Google PageSpeed Total Blocking Time issues. This score sometimes goes down to 300 ms, but a few minutes later goes to 1.500 ms! Nothing changed meanwhile. Tried with all minifications and Combine enabled and disabled. No apparent difference.

Do you have any idea?
Sincerely.

Example page: https://www.izreview.com/siemens-eq-3-espresso-coffee-machine-review/

The page I need help with: [log in to see the link]