[Fermé] WPML doesn't activate all sites in multi-site

Background of the issue:
I updated WPML to version 4.8 manually via 'Upload Plugin'->Commercial, selecting the WPML Multilingual CSM plugin and choosing 'Activate after download'. I expected both sites in my multi-site installation to be activated. The issue can be seen at lien caché.

Symptoms:
After pressing 'Download', only one of the two sites in the multi-site installation was activated. I had to activate the other site, lien caché, manually.

Questions:
Why did only one site activate after updating WPML in a multi-site installation?
How can I ensure both sites activate automatically after an update?