Migration from bootstrap 4 to 5 broke my powerbi-client embedded report refresh function

This was working perfectly before I upgraded bootstrap 4 to 5, and now something isn’t happening correctly.

We are using an embedded report viewer as outlined in the Microsoft-provided example.

Here is the code that sets up these buttons:

    document.getElementById('btnViewFullScreen')
        .addEventListener('click', () => { this.embeddedReport.fullscreen(); this.LogEvent("View Fullscreen", ""); });
    document.getElementById('btnPrint')
        .addEventListener('click', () => { this.embeddedReport.print(); this.LogEvent("Print", ""); });
    document.getElementById('btnRefresh')
        .addEventListener('click', () => { this.embeddedReport.refresh(); this.LogEvent("Refresh", ""); });
    document.getElementById('btnReset')
        .addEventListener('click', () => { this.embeddedReport.reload(); this.LogEvent("Reload", ""); });

btnRefresh is the broken one, all other buttons/functions work correctly. Here is the button markup:

<li class="nav-item active">
    <button class="btn bg-envision" id="btnRefresh" title="Refresh visuals-when the data has been updated, refreshing will update all visuals with the latest data" aira-label="Refresh visuals-when the data has been updated, refreshing will update all visuals with the latest data">
        <i class="fas fa-redo-alt"></i>
    </button>
</li>

Here’s the result, I’ve traced it to this line in the refresh function:

I have watched this many times and first pass through _a.label is 0, then it’s 2, then it’s 3. I don’t understand what’s going on in here. Ultimately this is the exception that surfaces:

Any pointers or any information at all is helpful.