This has nothing to do with the Big Bang theory. The universe is expanding; we have direct observational evidence of that. All this means is that the early period of the universe, which we are just seeing now, might not match our theories.
The Big Bang theory and the early history of the universe are tied together at the hip.
The universe expansion could have many other explanations—up to now scientists have chosen to reject them—now they will be forced to take a second look at other possibilities.
If I had to take a wild guess it would be that the universe it itself in a closed loop—and there was no “beginning”—and the expansion is just the current phase of the loop.
This would obviously be difficult to see unless you look far enough back in time and found out there was no “beginning” when you saw some past point where was a contraction before the expansion.