Contact Form 7 error on iPhone

My customers with an iPhone complain they cannot use the contact form on my website.

They get the error message with orange border, which according to CF7 docs means it’s marked as spam.

Since CF7 only accepts recaptcha v3 (no longer v2) it’s probably the combination of CF7 + recaptcha v3 + iPhone that results in a false SPAM alert.

How can this be fixed???