Height property of ::after pseudo-element of custom-file-label class is an error in IE11.

[nk-aoi]

height property of ::after pseudo-element of custom-file-label class is an error.
Because "calc" is nested.
https://getbootstrap.com/docs/4.0/components/forms/#file-browser

<div class="custom-file">
  <input type="file" class="custom-file-input" id="customFileLang" lang="es">
  <label class="custom-file-label" for="customFileLang">Seleccionar Archivo</label>
</div>

In IE 11, "calc" can not be described in calc()...
calc((2.25rem + 2px) - 1px * 2)

Operating system and version: Windows8.1 / Internet Explorer 11