sysupgrade is constantly failing

Hi *,
I've been experiencing issues upgrading my -current machines to the next snapshots by upgrading via `sysupgrade -ns`.
I receive the following output:

Fetching from https://ftp.spline.de/pub/OpenBSD/snapshots/amd64/
SHA256.sig 100%
|**************************************************************************************************************************************************| 2141
00:00
Signature Verified
INSTALL.amd64 100%
|*************************************************************************************************************************************************| 43512
00:00
base66.tgz 100%
|**************************************************************************************************************************************************| 238 MB
01:07
bsd 100%
|**************************************************************************************************************************************************| 18099 KB
00:05
bsd.mp 100%
|**************************************************************************************************************************************************| 18184 KB
00:06
bsd.rd 100%
|**************************************************************************************************************************************************| 10100 KB
00:04
comp66.tgz 100%
|**************************************************************************************************************************************************| 74360 KB
00:21
game66.tgz 100%
|**************************************************************************************************************************************************| 2745 KB
00:01
man66.tgz 100%
|**************************************************************************************************************************************************| 7453 KB
00:03
xbase66.tgz 100%
|**************************************************************************************************************************************************| 22912 KB
00:07
xfont66.tgz 100%
|**************************************************************************************************************************************************| 39342 KB
00:16
xserv66.tgz 100%
|**************************************************************************************************************************************************| 16766 KB
00:07
xshare66.tgz 100%
|**************************************************************************************************************************************************| 4499 KB
00:02
Verifying sets.
(SHA256) man66.tgz: FAILED
(SHA256) xbase66.tgz: FAILED
(SHA256) xfont66.tgz: FAILED
(SHA256) xserv66.tgz: FAILED
(SHA256) xshare66.tgz: FAILED

And that's not even an issue with the specific mirror. I've tried several.

I'd appreciate your help ? Being unable to upgrade kind of sucks.
Thanks for your time !

Best regards,
Stephan