I don't believe it. It's an elemental thing like a control scheme that we're talking about and I can hardly imagine that Nintendo at this late stage realized that it's not working. This is so basic that it has to be done in the very early stages of development, but now, two months before release someone comes by and says it doesn't work? This doesn't make sense, really.

That's because it is just a rumor. I think you are the only one on this thread who spot this nonsense

According to the info we have, the game went into QA at Nintendo of Europe in Mid january where where the rumor caught fire about the issues. And he reported them. here a quate form the originial

"We've since contacted Robertson directly and he's elaborated a little more. He says that Nintendo's QA department is very concerned with how players will react to the "complex" motion controls - which have come under fire in the past - and that the entire project feels "disjointed".

http://www.nintendolife.com/news/2016/02/rumour_star_fox_zero_facing_development_niggles_another_delay_could_happen

It also says NoE was expected to fix this issue, in some way.

So this is not a new issue, this was even stated as one of the Official reasons why they delayed the game. In no way did this pop up only 2 month from release.

Lastly, Liam is a very trusted source, while nothing he says should be taken as fact, but I would give him the benifit of the doubt.