[Tex/LaTex] fancyhdr – anomalous behaviour on first page


I am having trouble typesetting multi-line headers using fancyhdr
The header on the first page behaves differently than the header on subsequent pages. The first page header has no depth, but produces a greater vertical displacement on subsequent pages.

Here is a sample tex file to illustrate the difficulty



\chead{line 1\\line 2\\line 3\\line 4\\line 5\\line 6\\line 7\\line 8}




page 1 \newpage
page 2 \newpage
page 3 


Best Answer

You get a warning when you compile your MWE:

Package Fancyhdr Warning: \headheight is too small (12.0pt): 
 Make it at least 94.54448pt.
 We now make it that large for the rest of the document.
 This may cause the page layout to be inconsistent, however.

Adding \setlength{\headheight}{96pt} fixes the problem.