Yes, what you're experiencing with Advantage+ Audience defaulting to ON when duplicating a campaign, especially with Lookalike (LAL) targeting, is something many advertisers are noticing. Meta seems to be quietly enforcing more automation, even when you’re trying to maintain a controlled setup.
So what I observed is,
In Scenario 1, you manually turned off Advantage+ Audience, so Meta stuck strictly to your LAL. As a result, the targeting was narrower, which can often increase CPR (Cost per Result) due to limited reach.
In Scenario 2, when you duplicated the campaign, Meta auto-enabled Advantage+ Audience, and in some cases, the option to turn it off, “Switch to original audience setup”, is no longer shown. This isn't a glitch; it's by design on some accounts.
Why is this happening?
Meta is actively transitioning advertisers toward broad audience strategies. With Advantage+ Audience, your LAL is treated more like a suggestion, and Meta has the freedom to expand targeting beyond your selected group, all in the name of performance optimization.
This aligns with Meta’s wider strategy: automation-first ad delivery using machine learning signals, rather than strict, manual targeting.
What you can do:
Rebuild from scratch instead of duplicating, this sometimes restores the manual audience option.
Try Ads Manager on desktop, not Business Suite or mobile. The toggle occasionally appears in the full interface.
If all else fails, you may be stuck with Advantage+ ON, Meta has made it so that not all accounts see the same toggles, depending on campaign type, budget, or delivery history.
Meta is clearly nudging advertisers to rely more on platform-driven optimization. While this can lead to better results in broad campaigns, it also limits controlled testing environments, especially when working with LAL-based ad sets.