In other words, they are saying we are unsure how supply chain...

In other words, they are saying we are unsure how supply chain disruptions etc will affect our timeline.

I also hold ANS, who's mega Mbalam-Nabeba iron ore, rail and port project in Cameroon/Congo was meant to commence with the laying of the first stone:
by end of 2021
then by end of Feb 2022
then in the 1/4 Q 2022
then first half 2022
now by end of 2022

Chill, as this is not confined to this project alone.
At least you have certainty this project is moving forward.

It's always better to under-promise and over-delivered than vice versa.