garbled/warped display

[7z3m]

example:

    * S: '/var/tmp/portage/media-libs/fontconfig-2.15.0-r1/work/fontconfig-2.15.0'
                                                                                ... done!
                                                                                         Dependency resolution took

                      [ebuild   R    ] media-libs/fontconfig-2.15.0-r1 [2.15.0-r1]

                                                                                  Would you like to merge these packages? [Yes/No] Interrupted.

only started happening when i compiled vis text editor with curses instead of ncurses. happens in text editor and terminal (st) - often after i enter/exit vis. it has been happening frequently, not rarely. clearing the screen doesn't fix it, i have to close and reopen terminal.

linux distro: gentoo