Fixing polarity can be a pain especially if everything is set up in the air already. Did you know that you can actually detect polarity by following a process?
Measuring each speaker, setting your delay locator and changing the delay locator in your audio analyzer so that it will automatically update continuously helps in detecting polarity before set up. If in case there is inversion, you need to track down the cause by swapping out cables, swapping red and black banana plugs or by testing it out.
Read more about this here: https://theproaudiofiles.com/sound-system-polarity-problems/