You get the change information for the original revisions that were used to create a file via integrate. But subsequent integrates don't carry forward the change comments for the revisions being integrated. For example:

//test/a/foo.txt #1 = add //test/a/foo.txt #2 = edit //test/a/foo.txt #3 = edit //test/a/foo.txt #4 = edit //test/a/foo.txt #5 = edit

//test/b/foo.txt #1 = add via integrate from //test/a/foo.txt#1,3 //test/b/foo.txt #2 = edit //test/b/foo.txt #3 = edit via integrate from //test/b/foo.txt#4,5

p4 filelog -i //test/b/foo.txt

... #3 change 503 integrate on 2002/08/06 by dfogleso at dfogleso-t21 (text) 'Anoth er integrate from "a" to "' ... ... copy from //test/a/foo.txt#4,#5 ... #2 change 502 edit on 2002/08/06 by dfogleso at dfogleso-t21 (text) 'An update on codeline "b". ' ... #1 change 499 branch on 2002/08/06 by dfogleso at dfogleso-t21 (text) 'Integrat ion from codeline "a" t' ... ... branch from //test/a/foo.txt#1,#3 //test/a/foo.txt ... #3 change 498 edit on 2002/08/06 by dfogleso at dfogleso-t21 (text) 'Another up date on codeline "a".' ... ... branch into //test/b/foo.txt#1 ... #2 change 497 edit on 2002/08/06 by dfogleso at dfogleso-t21 (text) 'An update on codeline "a". ' ... #1 change 496 add on 2002/08/06 by dfogleso at dfogleso-t21 (text) 'Initial add of file. '

This is on 2001.1. I don't know if 2002.1 (or earlier versions) work differently.

This is exactly as it's described to work. From "p4 help filelog":

The -i flag follows branches. If a file was created by branching, 'p4 filelog' also lists the revisions of the source file, but only those revisions leading up to the branch point.