Phantom preload wont disappear

I’m having trouble with an old homepage banner image being preloaded and can’t seem to get rid of it. I’m almost certain that Autoptimize is loading it regardless of having never used the ‘LCP image to preload’ feature. (I had used a function in my child theme to preload home page banner.)

When I deactivate Autoptimize, the preload disappears. When I activate Autoptimize it reappears.

I’ve cleared caches countless times (Autoptimize, Divi, Wp-Fastest cache) deactivated WP-Fastest cache etc but the old preload script stubbornly refuses to go. Any help appreciated.

Thanks

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