You have to fill in box 52 and53. The sun of amounts in boxes 52 and 53 add up to what in box 21. Nothing eill show up in schedule 3 unless you enter amounts in 52 and 53. Schedule 3 is not populated with amount in 21 but with what is in boxes 52 and 53.
With regards to T5008 you have to input the date of sale in one of the boxes. Unless you fill the dste box, it will not populate schedule 3
I am using preminm addition of turno tax. It worked for me as explained above. Try that out it should work. Unless of course the issue is with business version of turbotax
