bold text is not showed correctly in viewer

[baiterry]

Describe the bug

the viewer do not show bold text but the string **
e.g. **HBuilder:**HBuilder

To Reproduce

init the viewer with initialValue:

new toastui.Editor.factory({
        el: viewRef.value!,
        viewer: true,
        initialValue: '**HBuilder:**HBuilder'
});

Expected behavior

view should show bold text like:

Screenshots

when in editor:

but in viewer:

Additional context

i find out the text without special character : can show bold: HBuilderHBuilder