Inconsistent behavior from map

I’ve got map that grabs the title and url from the browser and generates a markdown link from it:

inoremap <Leader>gg [<esc>:set fo-=t <cr>:silent !~/bin/copy_safari_title.osa <cr>:let @+ = substitute(@+, '|', '', 'g') <cr>a<c-r>+](<esc>:let @+=''<cr>:silent !~/bin/copy_safari_url.osa <cr>:let @+ = substitute(@+, '(', '%28', 'g')<cr>:let @+ = substitute(@+, ')', '%29', 'g')<cr>a<c-r>+)<esc>:set fo+=t <cr>a  <left>

When a buffer is first opened and I run this map, it works flawlessly. But the next time it is called, it’s hit or miss. It will usually jump up one line and insert the link in the wrong place. Sometimes it jumps several lines. It’s really weird and driving me crazy. There doesn’t seem to be any rhyme or reason to how it behaves.

The movie below show me doing <leader>gg and it working as expected. Then I drop down two lines and run the same command. This time, it gets inserted in the middle of the previous link.

UPDATE

It gets weirder. I changed the map to this:

inoremap <leader>gg <esc>:set fo-=t <cr>:!~/bin/copy_safari_title.osa <cr>:let @+ = substitute(@+, '|', '', 'g')<cr>:let @x=@+<cr>:!~/bin/copy_safari_url.osa <cr>:let @+ = substitute(@+, '(', '%28', 'g')<cr>:let @+ = substitute(@+, ')', '%29', 'g')<cr>:let @y=@+<cr>:set fo+=t <cr>:let @z='[' . getreg('x') . '](' . getreg('y') . ')'<cr>"zpa  <left>

But the same thing happens!