Stumbled upon this Kael Raid guide:
http://eqdiary.tripod.com/quests/kael.htm
The Arena
"After people were tramping through Kael totally unmolested, Sony decided to make us earn our keep by putting in giants that see invisible. That starts at the top of the ramp leading to the arena. At the top will be two pairs of giants, usually frost but some times storm, that will see invis and sneaking rogues."
and
"To the north of the arena is a bridge leading to the temple. Now, a warrior worshipper of Rallos Zek can walk through Kael largely unmolested, although he's dubious to everything until he works on his faction. Here, though, everyone is KoS."
...the site mentions the Statue, so it's probably a little after Velious launch. Web Archive does not have an old copy of this page.