Input group addon right corner becomes square when adding a validation element

[jeffreymeng]

It seems that when I add a invalid-feedback class to a input-group, the corners on the right stop being rounded.

I made a JSFiddle here.
It also dosen't work on the bootstrap docs here (Click submit while the username field is empty and the username field's corners are cut off too).

Not working

<label for="name">Short Link:</label>
<div class="input-group mb-3">
	<div class="input-group-prepend">
		<span class="input-group-text" id="name-addon">https://jkmls.tk/</span>
	</div>
	<input type="text" class="form-control is-invalid" id="name" aria-describedby="name-addon">
	<div class="input-group-append">
		<button class="btn btn-primary" type="button">Random</button>
	</div>

	<div class="invalid-feedback" id="name-validation">
		Please choose a username.
	</div>
</div>

Working

All i did was comment out the validation text:

<!--<div class="invalid-feedback" id="name-validation">
	Please choose a username.
</div>-->

[mdo]

Duplicate of #25110.