How can i avoid Jest reporting coverage from unchanged files which are referred in other test.

I am using jest --coverage --changedsince.

Eg:- I have changes in file 1.ts, my 1.test.ts refers to 2.ts. My coverage report includes both 1.ts as well 2.ts. Also, the coverage is indicated only by the lines coverage through 1.test.ts and not 2.test.ts