slarm64: slackpkg GPG check fails

Lately, on my Rock-Pi 4 with slarm64, when launching
Code:# slackpkg update && slackpkg upgrade-all I get this error message: Code:[...]
Downloading http://dl.slarm64.org/slarm64/slarm64-current/testing/MANIFEST.bz2...
--2021-10-04 19:49:36-- http://dl.slarm64.org/slarm64/slarm64-current/testing/MANIFEST.bz2
Resolving dl.slarm64.org (dl.slarm64.org)... 193.151.15.132
Connecting to dl.slarm64.org (dl.slarm64.org)|193.151.15.132|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 14 [application/x-bzip2]
Saving to: /tmp/slackpkg.mJ4R82/testing-MANIFEST.bz2'

/tmp/slackpkg.mJ4R82/testi 100%[=====================================>] 14 --.-KB/s in 0s

2021-10-04 19:49:36 (483 KB/s) - /tmp/slackpkg.mJ4R82/testing-MANIFEST.bz2' saved [14/14]

Checksums
Downloading http://dl.slarm64.org/slarm64/slarm64-current/CHECKSUMS.md5...
--2021-10-04 19:49:36-- http://dl.slarm64.org/slarm64/slarm64-current/CHECKSUMS.md5
Resolving dl.slarm64.org (dl.slarm64.org)... 193.151.15.132
Connecting to dl.slarm64.org (dl.slarm64.org)|193.151.15.132|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 341770 (334K)
Saving to: /tmp/slackpkg.mJ4R82/CHECKSUMS.md5'

/tmp/slackpkg.mJ4R82/CHECK 100%[=====================================>] 333.76K 1.20MB/s in 0.3s

2021-10-04 19:49:36 (1.20 MB/s) - /tmp/slackpkg.mJ4R82/CHECKSUMS.md5' saved [341770/341770]

Downloading http://dl.slarm64.org/slarm64/slarm64-current/CHECKSUMS.md5.asc...
--2021-10-04 19:49:36-- http://dl.slarm64.org/slarm64/slarm64-current/CHECKSUMS.md5.asc
Resolving dl.slarm64.org (dl.slarm64.org)... 193.151.15.132
Connecting to dl.slarm64.org (dl.slarm64.org)|193.151.15.132|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 691 [application/pgp-signature]
Saving to: /tmp/slackpkg.mJ4R82/CHECKSUMS.md5.asc'

/tmp/slackpkg.mJ4R82/CHECK 100%[=====================================>] 691 --.-KB/s in 0s

2021-10-04 19:49:36 (19.3 MB/s) - /tmp/slackpkg.mJ4R82/CHECKSUMS.md5.asc' saved [691/691]

ERROR: Verification of the gpg signature on CHECKSUMS.md5
failed! This could mean that the file is out of date
or has been tampered with. If you use mirrors.slackware.com
as your mirror, this could also mean that the mirror to
which you got redirected is not yet updated with the most
recent changes in the Slackware tree.

You need the GPG key of slarm64 AArch64 <security@slarm64.org>.
To download and install that key, run:

# slackpkg update gpg

You can disable GPG checking too, but it is not a good idea.
To disable GPG, edit slackpkg.conf and change the value of the CHECKGPG
variable to off - you can see an example in the original slackpkg.conf.new
file distributed with slackpkg.After Code:# slackpkg update gpg

Getting key from https://www.slackware.com/infra/keys/arm/GPG-KEY
Slackware Linux Project's GPG key addeddoingCode:# slackpkg update && slackpkg upgrade-all still fails.

Changing the mirror doesn't help either.
For updating my system I need to disable CHECKGPG in /etc/slackpkg/slackpkg.conf, but that's not recommended.

Any ideas how I can get rid of this error without disabling CHECKGPG?