> This behaviour likely goes under "what did you expect to happen?" - if the service describes its intended semantics and the agent follows that description, is that misalignment or something different?

Something different.

Don't give the AI access to data you don't want it giving out. Any AI you use is no better than some fresh out of college intern at best. They see 'email address required' and they put the email address into it because you instructed them to do a task that required passing over your email address and if you didn't want them to do it why would you have given them that task?

If there is any other issue here it would be regulatory. I could see the EU framing this as the AI company illegally sharing your PII information if it passed your email address to another company without your explicit permission.