There's been very few interstellar objects he's claimed as alien, in fact only one - and for onomua (or however it was spelt) he also said the most likely outcome would be a natural object. His expedition to recover metal spheroids from the ocean floor was a fascinating one which garnered a lot of support and I believe still had value in devising methods to recover impact materials from underwater.

So really it's the same thing, he gets a lot of aggressive pushback online for mentioning 'aliens', but generally speaking nothing he says or does is actually that baseless.