iFrame from plugin not showing in iOS

I am using the GiveWP plugin to handle donations on my site, and their multi-step form which injects an iframe into the page to show the form is not showing up on recent versions of iOS on iPhones. I have disabled all plugins, including bold builder, and the iframed form then shows up fine. As soon as I re-activate Bold Builder, the iframw no longer shows up. I’ve also used the plugin on other sites, and have had no problems. It seems like it’s a specific conflict with Bold Builder. Could someone look into this for me?

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