Startify opens shells in vim

When I open neovim, my startify screen opens but has the output from a new shell window.

In my init.vim I have the line
> let g:startify_bookmarks = systemlist("cut -sd' ' -f 2- ~/.NERDTreeBookmarks")

to show my NERDTree Bookmarks, thats the only thing I changed about it.

When I open vim with the same config, It's just normal

Start by reproducing the issue in Neovim with the init.vim setting for g:startify_bookmarks and compare it with the same configuration in Vim. Determine why the systemlist("cut -sd' ' -f 2- ~/.NERDTreeBookmarks") command produces shell output on the Startify screen; done means bookmarks still appear without the shell output, while Vim behavior remains unchanged.

Written by the indexing model from the issue text.