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Open /etc/env.d/70less.

Change from:

LESS="-R -M --shift 5"

To:

LESS="-I -R -M --shift 5"

Also make sure that /etc/env.d/00basic is setting LESS as the pager.

PAGER="/usr/bin/less"

The above instructions works for Gentoo.
If your distro doesn't have /etc/env.d/ you can add those lines to /etc/profile.