mt77 : It's not a big issue. In fact My current online I-94 is completely different than what my current valid I-94 is. After returning back with H1B stamping, I had extended my H1B which came with approval notice and new i-94 validity period and new number. Online still shows old number which has already expired.
If you want to update that- call CBP office or visit one nearest to you. I think you might have to make appnt first.There is one usually inside the airport too.
Since you have a stamp in you PP with arrival date, you have a way to prove your case.