In the header section of a Pegasus Mail message-reader window, some subject lines appear with unwanted spaces in the middle. An example from a message received today: shown as

Subject: Order delivered: Cupri nol Garden Furniture Sta…

"Cuprinol" is the intended word, without a space in the middle. It's shown correctly in the New mail folder contents list, but shown with the space in the top of the message reader.

The raw view of the message shows this for the subject, with a line break for continuation where the inappropriate space is:

Subject: =?UTF-8?Q?=F0=9F=93=A6_Order_delivered:_Cupri?=
 =?UTF-8?Q?nol_Garden_Furniture_Sta=E2=80=A6?=

According to RFC 2047, section 6.2,

When displaying a particular header field that contains multiple 'encoded-word's, any 'linear-white-space' that separates a pair of adjacent 'encoded-word's is ignored. (This is to allow the use of multiple 'encoded-word's to represent long strings of unencoded text, without having to separate 'encoded-word's where spaces occur in the unencoded text.)

This is very far from a major problem, but it is a minor annoyance. The extra space is not new in Pegasus Mail 4.80.