The pension doesn’t affect CPP, she won’t lose any CPP benefit.
Defined-benefit Pension plans vary a lot, but usually, the way it works is that if the workplace pension is started before 65, it provides a bridge benefit to 65 on top of the regular pension payment.
Pension plans assume you start CPP at 65, whether you do or not, and that bridge benefit is meant to provide a CPP-like amount to 65, and then they stop paying it.
Look at her pension booklet, it should explain, and her yearly statement should give an estimate of both the bridge benefit and the pension depending on when she takes it.
If you’re still not clear, you can ask the Pension Plan provider.
The app allows you to enter a bridge benefit amount, separate from a work pension amount, that ends at 65. In INCOMES, select Defined benefit bridge pension. The regular pension should be entered as a Defined benefit pension.