can't remove libtiff from qtimageformats_git.bbappend?

[P123]

Hi,
Would like to compile qtimageformats without libtiff support. I added below line in my qtimageformats_git.bbappend file
PACKAGECONFIG_remove = " libtiff"
tried this also PACKAGECONFIG_remove_pn-qtimageformats = " libtiff"

but still it gets compiled with tiff support? we are using meta-qt5 layer morty branch.

any suggestion?
Thanks.