Origin servers SHOULD NOT fold multiple Set-Cookie header fields into a single header field. The usual mechanism for folding HTTP headers fields (i.e., as defined in [RFC2616]) might change the semantics of the Set-Cookie header field because the %x2C (",") character is used by Set-Cookie in a way that conflicts with such folding.
"Fold" should be replaced with "combine" to make this paragraph consistent with the HTTP/1 specs (RFC 2616, RFC 7230).
https://www.rfc-editor.org/errata/eid6093 https://stackoverflow.com/questions/3241326/