Quick answer...Jeremiah 28:3 is a false prophecy by Hannaniah.
True but Jeremiah ratifies that prophecy in Jer 28:6 by saying Amen. After that statement by Jeremiah the prophecy was no longer false. Jeremiah does qualify which portion of the prophecy was ratified and the part of the utensils is ratified. So the issue with the 70 years ending with the utensils being returned persists.
I reread your post and you provide no proof that there's a link between the 70 years and the utensils being returned. The kingship of Babylon ends after 70 years but this is a separate event and the returning of the utensils only happens two years after that as was prophesied.
If you can provide me a scripture that shows explicitly that the 70 years ends with the utensils being returned I would be grateful as this will cause me to reinvestigate 607.