While v0.5 slowed down EVERYONE in spectator mode after any player triggered chunk generation, v0.5.1 will ONLY slow down players who most likely triggered chunk generation.

Also, to limit any possible performance impact due to some necessary (and already optimized) calculations, there is an internal cooldown of 10ms, whenever someone has been slowed down due to generating chunks. (This slowdown will still only apply to spectator-mode movement)

Meaning: even on a very slow machine with a lot of players, this should have pretty much no noticeable performance impact.