...and I'm loving every minute of it. I committed to seeing this through at least until they don't need me anymore, and I fully intend on meeting that obligation, and possibly well beyond that if the work continues to be fun.
You'll note how the shame is being attempted in this very comment thread. It makes me sad. :(
If it turns out that management is not thinking this way in your company, then great! But I think most people commenting skeptically here are familiar with situations where one over-achiever in the team sets an impossibly high standard for everyone else and thus unwittingly causes them harm.
This is also why it is usually not considered a problem when a person pursuing their individual passion project puts in crazy hours. If you work for yourself, you're not setting standards for anyone else.