It think there us a serious problem with T5008 handling in TurboTax. As noted, capital gains from T5008 MAY already be reported elsewhere. Also, depending on circumstances, may be capital gain (most likely) or income. The cost basis given by the investment broker is usually $0, which is almost certainly wrong. And in any event, the broker is unlikely to have the actual correct ACB. This fact is acknowledged by the CRA in their T5008 write-up. The fact that TurboTax will just blindly use an ACB value of $0 is a horrendous bug.
The problem is further complicated by the fact that TurboTax seems to Auto-fill the T5008 data during NETFILE. So even if you have all the correct Schedule 3 data in place, it will submit a bunch of incorrect duplicate T5008 data, with an incorrect ACB of $0. This results in an apparent huge capital gain that did not actually occur. And having been NETFILEd there is no way to fix it until the NOA comes. This is a very serious problem.
