The security option deduction on Line 297 of the Quebec return is equal to 25% of the benefit received,  50% may be available if certain conditions are met.  You can learn more here, but you should not have to override the entry.
@bibite26 

@bibite26 The deduction is the total of the amounts in boxes L-9, L-10, L-12 and L-13 of your RL-1 slip. It is equal to 25% of the benefit deemed received in the year (or 50% of the benefit if certain conditions are met). To learn more, see guide IN-253-V, Taxable Benefits.

For more information, Refer from this resource from Revenu' Quebec.