Osmose flags the linefeed characters in the inscription textfield as non-printable. The wiki page suggests | or slashes /, but this approach is problematic because real objects might contain those symbols.
Initially reported this as a bug on iD editor, but I was referred here.
Example node:
https://osmose.openstreetmap.fr/en/issue/cf0b4bd8-30b6-9aa4-b0e9-15e9c2894a27