`apk del --purge` does not delete "apk-new" files

I have this package with its config in /etc:

miniflux.conf
miniflux.conf.apk-new

Now delete this package:

$ doas apk del --purge miniflux
(1/3) Purging miniflux-openrc (2.0.44-r3)
(2/3) Purging miniflux-doc (2.0.44-r3)
(3/3) Purging miniflux (2.0.44-r3)
Executing busybox-1.36.1-r4.trigger
Executing mandoc-apropos-1.14.6-r8.trigger
OK: 6501 MiB in 1077 packages

But still have this file left

miniflux.conf.apk-new