Yep. That's the only thing "bad" about this monitor. However, this particular panel sucks at overclocking. The ASUS PG248Q has the same panel and I owned that monitor and just as professional reviewers found, overclocking it has unwanted artifacts (like, tons of tiny horizontal lines all over the panel). At 160Hz, it's tolerable. At 170Hz, it's almost intolerable but you might be able to ignore it if you try. At 180Hz, it's distracting. So, I never overclocked it.
So, don't feel too bad that you can't overclock the G2460PG because it would have undesirable effects anyway.
Not to mention just because one person couldn't get it a stable overclock out of it, doesn't mean yours or OPs wouldn't be stable. My Phenom II X4 955BE isn't stable above 3.8GHz, but that doesn't mean all of them are unstable above 3.8GHz. There are plenty of people who have gotten a stable 4.2GHz out of them just fine. And just like the Phenom II X4 955BE, all of the AOC G2460PGs are different, even if they are the same make and model.