Users receive error: Unable to load the reCAPTCHA image. The public key (6LdfYhgTAAAAAHUukLvPyeW-5I1QRy46e8S4Tf7Z) might be invalid for this domain when there are more than three donation forms on a page
This is a limitation of Google ReCaptcha API version 1.0 in that only one ReCaptcha is allowed per page. We were able to get around this by making each donation form use a different language. This makes it so that only on donation form renders on a page and thus only one ReCaptcha loads on the page.
Steps to Duplicate
Ensure reCAPTCHA is set up on the child site in Administration>Sites & Settings for Anonymous and provisional users when processing a payment
Create A simple donation form part with proceed directly to payments
Create a new page
Add three or more instances of the donation form part to the page