It is an issue, because the only evidence we have to go off of is her word. You can't say, "I filed a sexual harassment complainant with the senate", then when Biden calls the bluff to prove his side of the story, she says "okay I didn't use the term assault or sexual harassment, I maybe used the term uncomfortable". In your example you used an exact date, if we had an exact date to go off of, we could confirm Biden was in DC and a possible interaction with Reade occurred, or he might have been in another freaking country. A lack of details, and a changing of details is a massive issue. It makes it impossible to corroborate her story, and it makes it impossible for Biden to clear his name.