When you are on a private chat with another person and enable 'Block Copy, Forward, Sharing', when you send a link and the other person long-presses the blue underline text they will be prompted with the 3-option menu. The person you are on a chat with should not be able to see the 3-options.
Workaround: There is currently no known workaround for this issue. If you have experienced this, please reach out to support. https://fyihelp.zendesk.com/hc/en-us/requests/new
Device Affected: IOS & Android