@Steve ******
, The ONLY time a local immigration office won't sort out a bad stamp is if you forget to stamp in totally.
There were cases of people who entered by a land border but just walked past passport control without getting stamped in.
In their cases they HAD to go back to the border they should have stamped in at to get the stamp corrected.
I have never ever heard of someone with a wrong stamp (especially from flying in) have to go back to the airport they landed at and get the stamp corrected.