[BUG] v:count1 sometimes returns column number for mappings if returned expression moves cursor using `|'

[ZyX]

After launching
    echo $':echom "Here"\nsshsshss:redir! >messages\n:messages\n:redir 
END\n:qa!\n' | vim 
-u NONE -c 'so test-expr-count.vim' -c 'normal a...' -c 'normal ssssss'
I get the following output in messages file:

    Messages maintainer: Bram Moolenaar <b...@vim.org>
    0
    0
    0
    0
    0
    0
    Here
    1
    3
    1
    2
    1
    1

while expected to have all 1's. Contents of `test-expr-count.vim':
        function! DelNthSpace()
            echom v:count1
            return virtcol('.').'|'
        endfunction
        nnoremap <expr> s DelNthSpace()
I get almost the same results for `v:count' and any bar movements, but not with 
other movements and expressions. Tested on vim-7.3 and vim-7.3.62-r840c3cadb842.

bug2.sh
Description: application/shellscript

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