My son is a student and his 2019 employment shows he paid $1150 income tax. Prior to entering his T2202, TT shows a tax refund of $1135. After entering the T2202, this refund calculation drops to $1115. That's the first place this seems incorrect, next when I try to calculate what can be transferred to a parent, it show $0 federal and $0 provincial. I understand some of his tuition should have been used to drop his taxes payable to 0 (which it didn't accomplish) and the remainder should have been available to transfer to a parent, which again it didn't. I've done this step in past years and it works, but this time it doesn't. Is this a known fault in TT2019?
Your son's refund may have been higher prior to entering his T2202 - Tuition & Education Amounts Certificate as his tax return was originally showing a refund of the Canada Workers Benefit (CWB) that full-time students are not eligible for. As soon as you enter a T2202A that has 4 or more full-time months on it, the credit is removed and your refund is reduced.
As for the transfer amount showing as Zero, it is possible if your son needed to use the Tuition and Education Amounts on his own return first. If he needed to use all of the amounts or over $5,000 then he would have Zero to transfer. Any excess would be carried forward on his return.
Without seeing the actual tax return and how much income was made and what type, it's hard to determine from this forum how much of the Tuition is being used.
Please see this information on transferring and carrying forward tuition: CRA - Transfer or carry forward amount and TurboTax FAQ