I didn't see a solution for this elsewhere online, so I'm posting it here just in case anyone is searching for it.

If you're using the default Laravel Elixir install to compile bootstrap-sass, you may be running into an issue where some items aren't aligned properly, in particular the bottom of the input on a input-group may be misaligned similar to what is shown here: https://github.com/twbs/bootstrap/issues/15840

This describes the problem caused by the default precision of the SASS compiler (including the one that comes with Elixir): https://github.com/twbs/bootstrap-sass/issues/409

If you're compiling bootstrap-sass with the SASS version that comes with Elixir, you have to add elixir.config.css.sass.pluginOptions.precision = 10; to your gulpfile.js after your "var elixir" is defined. Otherwise the default precision of 5 causes alignment issues with input-group and other Bootstrap elements.