(Solved) Why does the LP EQ cause latency even in "Bypass" mode?

All linear phase eqs tend to have quite a lot of latency because they need to do a lot of calculations to prevent phasing issues and need to know what the data after the chunk they're currently handling looks like.

Limiters and compressors which "look ahead" have latency for the same reason. Other typical serious latency inducers are some impulse based or convolution reverbs, or plugins which simply need a lot of time, relatively speaking, to do their thing. Audio recording and processing makes the kind of latency even a gamer would never notice in a game, never mind someone doing typical office tasks a major issue. They'd almost certainly never notice 20 or so milliseconds pause while the computer catches up but we do.

Waves are unusual in that they publish the latency introduced by their plugins under the tech specs on each plugin's page. Even if you don't have any of Waves' plugins it's worthwhile taking a look at some because it gives an idea of the kind of processes that cause latency.