Your link provides no info on the ‘last sample’.
There is nothing on the "second testing" all articles keep pointing to "inconsistencies" rather than actual re-testing and dating; then too, the fire the Shroud was involved in skewed the testing due to carbon from the fire settling on the Shroud. It's interesting that some article call it a forgery. You only forge something that exists as a real item.
The science is still not settled on its actual age. Perhaps you can explain how something like this could be forged given the technology of that age.