Comment by noelwelsh

Glitches are transient incorrect values due to delays in propagating values. Imagine a diamond pattern of reactive values like:

    a = 0, 1, 2, ...
    b = a
    c = a
    d = b + c

d should be 0, 2, 4, ... but if, say, b updates and d sees this update before c updates then you can get incorrect values in d.