Hello,
To add to your bug report I would like to point out that the author
has this topic as a FAQ. Thanks.
from http://home.flash.net/~marknu/less/#tite
Can less leave the screen alone when it quits?
When less quits, it sends the "te" termcap string to the terminal.
Exactly what that does depends on the system you are using, the type
of terminal, and your version of termcap. On some systems, it does
nothing; on others it restores the screen to the state it was in when
less started, thus erasing from the screen the last page of the file
which less was viewing. If you don't like the behavior of "te" on your
system, you can disable the sending of the "te" string by invoking
less with the -X option. If you want "te" to do something different
(for example, restore the screen if it's not doing that already),
you'll have to figure out how to override the default termcap on your
system. Unfortunately, this is done differently on different systems,
so you'll have to check the documentation for your system.