I use the common plugin contact-form-7 and generated some extra tags following the settings.
It comes up with the following code:
<p>Contact Phone Number<br> <span class="wpcf7-form-control-wrap telephone"><input type="tel" name="telephone" value="" size="40" class="wpcf7-form-control wpcf7-text wpcf7-tel wpcf7-validates-as-tel" aria-invalid="false"></span> </p>
However, the css around line 2148 doesn't allow for these extra input types.
On line 2151 I had to add the following so the tel input area matched existing styling.
.content form input[type="tel"],
This is something you may want to look at for future updates.