As belltown mentioned in the thread you linked to, it is not normal for a Shoutcast server to include the ICY-Metadata unless you specifically request it. The fact that your server is sending it in every case would suggest that there's a configuration issue on your end. I think it's unlikely that contacting Roku support would provide you any more insight than that.
With that in mind, however, Roku added support for MP3 metadata to the
Audio SceneGraph component in firmware 7.2, albeit woefully underdocumented. It's not clear if that could be used for ICY metadata or not...
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