I am sure that there are updates still coming out to the TurboTax business software. Updates to software goes on throughout the tax season. What I do know and I have learned from my research on the subject of PPP loan forgiveness is that it does affect the basis (in the year forgiven).
The instructions I previously sent you are the IRS expanded guidance on reporting expenses used to obtain PPP Loan Forgiveness on Form 1120S, Schedule M-2. This is the guidance from the IRS to reconcile M-2.
The amount of the tax-exempt income (PPP loan forgiveness) would be reported on Schedule K-1, Box 16 with a Code B. See Entering PPP Loan Forgiveness
