If the contribution in January 2017 was for 2017, they would coded a return of contribution with codes J and 8. If the contribution was for 2016 they would have used J and P, I expect.
The reference that you cited is very misleading. It says, "If you withdraw contributions made during the current tax year you have until the end of the tax deadline (April of the following year) to redeposit the money back in your Roth IRA." What it doesn't say is that to be able to do so the contribution must be "withdrawn" by making a return of contribution, not by making a regular distribution.
Code T indicates a regular distribution made after you reached age 59½.
