It would be too laborious to edit manually the quoted formulas though. Without editing, they may cause confusion because they may look legit while being not correct. In the above example, the fraction has been turned into a multiplication and without reading the original post it's not possible to know that.
I talked to the Invision people several times about this but they refused to work on a fix (I understand that they don't know how to fix it and don't want to spend much time on it as the market share of technical forums is rather tiny). It's worth noting that this problem is specific to IPS: I tested other software (such as Xenforo) and they don't have this problem.