The type of income decides on which schedule the income from T5008 flow into.
When "Invesment" is selected, it flows into line 12100 as an other invertment income.
When "Capital gain" is selected, it flows into schedule 3 and taxed as an capital gain.
It's the slip issuer's responsibility to display the correct information on this slip and report to CRA.
So back to the original question, since T5008 can include these two types of income, it has to reply on the information provided on the slip to classify this income. If the slip (or from AFR) had this "investment" value, Iit's my understanding that S3 would have been autopopulated.
