Lost all My Custom Body Field Contents

I had a custom body field of type email. I had a situation where I needed to enter two email addresses, but it wouldn't accept a separator like a comma or semicolon. I changed the field from type email to type free form text. I pulled up my transaction to add the second email address, and discovered that everything in my custom email field was gone.

I could understand this happening if I was given a warning that all my information was going to be lost if I converted the type, but I didn't get a warning. I could also understand it if I was trying to convert incompatible types (e.g., a text field to numeric). However, anything that fits in an email field can fit in a free form text field and I didn't get a warning. There's really no excuse to delete data without giving any warning at all.