When this snippet is not wrapped with display:grid, it works fine.
<div class="input-group mb-3">
<input type="text" class="form-control" placeholder="Recipient's username" aria-label="Recipient's username" aria-describedby="basic-addon2">
<div class="input-group-append">
<button class="btn btn-outline-secondary" type="button">Button</button>
</div>
</div>
However, when it is wrapped with display:grid:
.wrapper{
display: grid;
}
<div class="wrapper">
<div class="input-group mb-3">
<input type="text" class="form-control" placeholder="Recipient's username" aria-label="Recipient's username" aria-describedby="basic-addon2">
<div class="input-group-append">
<button class="btn btn-outline-secondary" type="button">Button</button>
</div>
</div>
</div>
https://i.sstatic.net/W0SSv.png
This input field appears to be a part of a larger CSS grid layout.