Hi, thank you for using Intuit turbotax Live Community
The amount on line 434 of the Quebec TP1 is calculated on the TP1 schedule I. TurboTax, in addition to entries for dependant(s), would prompt for entries on:
1) RL 30
2) RL 24 and
3) Entries for prior year line 275 income:
These three entries are required for TurboTax to calculate the amount for line 434 of the TP1.
If I were to guess, 3) is likely the issue needed to match Ministry of Revenue(MRQ). But, review entries for all three.
Hope this helps