Kmail2 does not show the encryption symbol in message list, if the mail is encrypted with inline pgp. For pgp/mime mails it works. see screenshot: the first mail is encrypted using inline pgp while the second one is encrypted using pgp/mime Reproducible: Always
Created attachment 84647 [details] screenshot of symbols first mail is encrypted using inline pgp second mail is encrypted using pgp/mime
maybe related to Bug 327241 ?
this is still valid in version 5.2.0
still valid for 5.7.3
still valid for 5.13.3