The team encountered an issue with a wishbone on its rear suspension which had affected both Mahindras and one of the ABT CUPRAs by the end of Free Practice 2 in Cape Town.
In conversation with Motorsport.com, Bertrand said: "It was a mixture of three things: the specification was probably a little bit under what was needed, there were probably some manufacturing imperfections and on top of that, it was a demanding, bumpy and fast track - with no real chance for mistakes. That's what guided our choice.
"The level of risk was troo high and that's why we made the extreme decision, but the correct decision. I think it was reasonable given ... the level of risk our drivers would have been exposed to. You cannot play with this."
The fix has been a simple one, with the turnaround time between Cape Town and Sao Paulo ample.
"We needed two-and-a-half weeks for the full process - reproducing the fault to the moment you identify a good solution. You then check the solution will be consistent and sustainable, and go to production of parts.
"I'm definitely confident [the problem is fixed] and definitely happy."