I was running the stress tests on some sites, and I found the same hydrationError in all of them: TypeError: Cannot create property 'current' on string 'MobileMenu' (the string varies between them).

I've been triaging it, and I believe this error occurs because they have a ref attribute in some HTML elements. As ref is also used by Preact, I assume at some point it tries to do something like ref.current === 'string' and produces this error.

Some sites are adding ref because they use other libraries like Vuejs or plugins like Curator.io, which also need the ref attribute.

This only happens when I run the stress testing script. If I paste the manual script into the browser console, I cannot reproduce it. I've checked the vDom with @DAreRodz, and the ref property is there, but it doesn't throw any error.

I tested 4000 sites and 8 of them had this issue:

• kxbox.com: TypeError: Cannot create property 'current' on string 'pc.kx.idx.banner1.ljxz'
• jhamiba.com: TypeError: Cannot create property 'current' on string 'MobileMenu'
• meidouya.com: TypeError: Cannot create property 'current' on string 'MobileMenu'
• wpdaxue.com: TypeError: Cannot create property 'current' on string 'MobileMenu'
• 22vd.com: TypeError: Cannot create property 'current' on string 'nofollow'
• knewsmart.com: TypeError: Cannot create property 'current' on string 'MobileMenu'
• mfisp.com: TypeError: Cannot create property 'current' on string 'MobileMenu'
• pro-q.it: TypeError: Cannot create property 'current' on string 'image'

Any idea about how should we approach this?