In the rendering dialog when clicking on the "folder" button next to the "output file" input field, the "open file" dialog which then opens ignores the path set in the "output file" input field. Instead, it always starts with the $HOME folder. This seems to be a regression, as formerly I think to remember that the "open file" dialog that opens from the rendering dialog correctly used the path as specified for the "output file", unless this is invalid. So the expected behavior is to restore the existing behavior, where "open file" uses the path given as "output file", unless it is invalid; only then it should revert to using $HOME as a sane fallback.
Should be fixed with Kdenlive version 17.04