I struggled with this issue for the last couple of weeks, but I finally figured it out.
In previous years, the date of disposition on the T5008 was available, but you didn't have to enter it.
This year, because the government was going to change the capital gains rate for dispositions made after June, you need to enter the disposition date on the form. If you leave it blank, it won't update your capital gains or schedule 3.
The problem is that when you use the CRA import feature, the disposition date is not part of the import.
After importing the T5008 form from the CRA, make sure to go to the form and enter the disposition date.
Also make sure to select Capital Gains or Investment Income from the type of income drop down or the form will be ignored by the software.
I tested this today using the latest update and it works.
