Unclear M_UNKNOWN_TOKEN: Invalid access token passed. error

[miri64]

We have the Matrix-Chat-Message deployed with a weekly run of a Github Action to report to a private matrix room. Sometimes it works perfectly as intentended:

Run fadenb/[email protected]
  with:
    homeserver: matrix.org
    token: ***
    channel: !UXNJuMzHTSAnwntbbN:utwente.io
    message: ✅ **PASSED**: Release tests
  [iotlab_creds, ] on "*workflow_dispatch*":
  https://github.com/RIOT-OS/RIOT/actions/runs/4091478349
  
    messagetype: m.notice
  env:
    DOCKER_MAKE_ARGS: -j
    SSH_AUTH_SOCK: /tmp/ssh-XXXXXXMx7W7H/agent.1558
    SSH_AGENT_PID: 1559
    pythonLocation: /opt/hostedtoolcache/Python/3.8.16/x64
    LD_LIBRARY_PATH: /opt/hostedtoolcache/Python/3.8.16/x64/lib
homeserver: matrix.org
channel: !UXNJuMzHTSAnwntbbN:utwente.io
token: ***
message: ✅ **PASSED**: Release tests
[iotlab_creds, ] on "*workflow_dispatch*":
https://github.com/RIOT-OS/RIOT/actions/runs/4091478349
messagetype: m.notice
sendEvent of type m.room.message in !UXNJuMzHTSAnwntbbN:utwente.io with txnId m1675512560763.0
Joined channel
Event sent to !UXNJuMzHTSAnwntbbN:utwente.io with event id $imxfmHpH-rPlaoBObauMvjAdm9B_hUjuehfuX9hD62I

However, most of the time, we get an M_UNKNOWN_TOKEN: Invalid access token passed. error, even though the token did not change:

Run fadenb/[email protected]
  with:
    homeserver: matrix.org
    token: ***
    channel: !UXNJuMzHTSAnwntbbN:utwente.io
    message: ❌ **FAILED**: Release tests
  [iotlab_creds, ] on "*schedule*":
  https://github.com/RIOT-OS/RIOT/actions/runs/4209315115
  
    messagetype: m.notice
  env:
    DOCKER_MAKE_ARGS: -j
    SSH_AUTH_SOCK: /tmp/ssh-XXXXXXutbYub/agent.1559
    SSH_AGENT_PID: 1560
    pythonLocation: /opt/hostedtoolcache/Python/3.8.16/x64
    LD_LIBRARY_PATH: /opt/hostedtoolcache/Python/3.8.16/x64/lib
homeserver: matrix.org
channel: !UXNJuMzHTSAnwntbbN:utwente.io
token: ***
message: ❌ **FAILED**: Release tests
[iotlab_creds, ] on "*schedule*":
https://github.com/RIOT-OS/RIOT/actions/runs/4209315115
messagetype: m.notice
sendEvent of type m.room.message in !UXNJuMzHTSAnwntbbN:utwente.io with txnId m1676700716517.0
(node:61474) UnhandledPromiseRejectionWarning: M_UNKNOWN_TOKEN: Invalid access token passed.
    at parseErrorResponse (/home/runner/work/_actions/fadenb/matrix-chat-message/v0.0.6/dist/index.js:51078:13)
    at /home/runner/work/_actions/fadenb/matrix-chat-message/v0.0.6/dist/index.js:51033:17
    at Request._callback (/home/runner/work/_actions/fadenb/matrix-chat-message/v0.0.6/dist/index.js:50967:9)
    at Request.self.callback (/home/runner/work/_actions/fadenb/matrix-chat-message/v0.0.6/dist/index.js:71728:22)
    at Request.emit (events.js:314:20)
    at Request.<anonymous> (/home/runner/work/_actions/fadenb/matrix-chat-message/v0.0.6/dist/index.js:72697:10)
    at Request.emit (events.js:314:20)
    at IncomingMessage.<anonymous> (/home/runner/work/_actions/fadenb/matrix-chat-message/v0.0.6/dist/index.js:72619:12)
    at Object.onceWrapper (events.js:420:28)
    at IncomingMessage.emit (events.js:326:22)
(node:61474) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:61474) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
Error sending event M_UNKNOWN_TOKEN: Invalid access token passed.
    at parseErrorResponse (/home/runner/work/_actions/fadenb/matrix-chat-message/v0.0.6/dist/index.js:51078:13)
    at /home/runner/work/_actions/fadenb/matrix-chat-message/v0.0.6/dist/index.js:51033:17
    at Request._callback (/home/runner/work/_actions/fadenb/matrix-chat-message/v0.0.6/dist/index.js:50967:9)
    at Request.self.callback (/home/runner/work/_actions/fadenb/matrix-chat-message/v0.0.6/dist/index.js:71728:22)
    at Request.emit (events.js:314:20)
    at Request.<anonymous> (/home/runner/work/_actions/fadenb/matrix-chat-message/v0.0.6/dist/index.js:72697:10)
    at Request.emit (events.js:314:20)
    at IncomingMessage.<anonymous> (/home/runner/work/_actions/fadenb/matrix-chat-message/v0.0.6/dist/index.js:72619:12)
    at Object.onceWrapper (events.js:420:28)
    at IncomingMessage.emit (events.js:326:22)
Error: M_UNKNOWN_TOKEN: Invalid access token passed.