Behind the scenes tension?

I recently read an article on Astaire, otherwise unrelated to this musical, but obliquely referring to the Band Wagon as the one instance in which Fred momentarily lost his composure and caused an "incident". I haven't been able to find out what it might actually be referring to, other than him perhaps minding Carisse's height.

I know other people had problems during the production, physical and psychological...but since I've read no books on Astaire yet, I'm quite at sea as to what was the "incident" the article was referring to might have been - and curious.

Any idea?