There's a low chance that this is a story about actual shortages that would indicate a weakness in Israel's missile defenses and very high chance this is about the weapons industry trying to milk more money from the US and Israeli governments.
Israel arrested some journalists for merely reporting on missile strikes. I have a hard time believing an Israeli weapons exec is dishing with a foreign paper on their weakness or the Jerusalem Post would get approval from the censors to write about it, even if the Financial Times had already done so.