Building a docker image failes on arm with alpine 3.14

Building a docker image failes on arm with alpine 3.14. 3.13 doesn't work either but 3.12 does. The build does work for amd64 and arm64, but not arm. arm and arm64 are built on the same ci runner machine.

Output:

Step 16/26 : RUN apk --no-cache add shadow &&   addgroup -g ${PGID} vikunja &&   adduser -s /bin/sh -D -G vikunja -u ${PUID} vikunja -h /app/vikunja -H &&   chown vikunja -R /app/vikunja
 ---> Running in cf37a6c07cf9
fetch https://dl-cdn.alpinelinux.org/alpine/v3.14/main/armhf/APKINDEX.tar.gz
4158026640:error:0D0D90AD:asn1 encoding routines:ASN1_TIME_adj:error getting time:crypto/asn1/a_time.c:330:
4158026640:error:0D0D90AD:asn1 encoding routines:ASN1_TIME_adj:error getting time:crypto/asn1/a_time.c:330:
4158026640:error:0D0D90AD:asn1 encoding routines:ASN1_TIME_adj:error getting time:crypto/asn1/a_time.c:330:
4158026640:error:0D0D90AD:asn1 encoding routines:ASN1_TIME_adj:error getting time:crypto/asn1/a_time.c:330:
4158026640:error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed:ssl/statem/statem_clnt.c:1913:
WARNING: Ignoring https://dl-cdn.alpinelinux.org/alpine/v3.14/main: Permission denied
fetch https://dl-cdn.alpinelinux.org/alpine/v3.14/community/armhf/APKINDEX.tar.gz
4158026640:error:0D0D90AD:asn1 encoding routines:ASN1_TIME_adj:error getting time:crypto/asn1/a_time.c:330:
4158026640:error:0D0D90AD:asn1 encoding routines:ASN1_TIME_adj:error getting time:crypto/asn1/a_time.c:330:
4158026640:error:0D0D90AD:asn1 encoding routines:ASN1_TIME_adj:error getting time:crypto/asn1/a_time.c:330:
4158026640:error:0D0D90AD:asn1 encoding routines:ASN1_TIME_adj:error getting time:crypto/asn1/a_time.c:330:
4158026640:error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed:ssl/statem/statem_clnt.c:1913:
WARNING: Ignoring https://dl-cdn.alpinelinux.org/alpine/v3.14/community: Permission denied
ERROR: unable to select packages:
  shadow (no such package):
    required by: world[shadow]
The command '/bin/sh -c apk --no-cache add shadow &&   addgroup -g ${PGID} vikunja &&   adduser -s /bin/sh -D -G vikunja -u ${PUID} vikunja -h /app/vikunja -H &&   chown vikunja -R /app/vikunja' returned a non-zero code: 1
time="2021-06-16T13:52:52Z" level=fatal msg="exit status 1"

Docker info:

$ docker version
Client: Docker Engine - Community
 Version:           20.10.7
 API version:       1.41
 Go version:        go1.13.15
 Git commit:        f0df350
 Built:             Wed Jun  2 11:57:03 2021
 OS/Arch:           linux/arm64
 Context:           default
 Experimental:      true

Server: Docker Engine - Community
 Engine:
  Version:          20.10.7
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.13.15
  Git commit:       b0f5bc3
  Built:            Wed Jun  2 11:55:14 2021
  OS/Arch:          linux/arm64
  Experimental:     false
 containerd:
  Version:          1.4.6
  GitCommit:        d71fcd7d8303cbf684402823e425e9dd2e99285d
 runc:
  Version:          1.0.0-rc95
  GitCommit:        b9ee9c6314599f1b4a7f497e1f1f856fe433d3b7
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

Code is here, relevant ci failure here.