Attachment filename is not properly decoded

I have received a MIME mail with the following attachment headers:

Content-Type: application/pdf;
        name="=?UTF-8?B?QlJOMzAwNTVDQjAyOTI4XzAwMDQ3Ni5wZGY=?="
Content-Description: odd-pages.pdf
Content-Disposition: attachment; filename="=?UTF-8?B?QlJOMzAwNTVDQjAyOTI4XzAwMDQ3Ni5wZGY=?="

It is displayed in the attachment list as "odd-pages.pdf", but trying to save it results in a suggesting ./=?UTF-8?B?QlJOMzAwNTVDQjAyOTI4XzAwMDQ3Ni5wZGY=?=.

This =?UTF-8?B?...?= encoding for Content-Disposition filename is the 'encoded-word' format defined in RFC 2047. Unfortunately that says:

An 'encoded-word' MUST NOT be used in parameter of a MIME Content-Type or Content-Disposition field, or in any structured field body except within a 'comment' or 'phrase'.

Maybe that filename field should be ignored if Content-Type with name is present? See also https://blog.nodemailer.com/2017/01/27/the-mess-that-is-attachment-filenames/

Reproduced with 1.11.4 and mutt-1-11-4-rel-208-g831ea9c5