This thread is resolved. Here is a description of the problem and solution.
How can I disable post details after translation on transcargo theme?
Client edited the translation using the WordPress standard editor instead of using the WPML Translation Editor and the issue is resolved now.
Situations like this occur mostly when a theme is not WPML-compatible like the one in our current case. You can find all the officially-recognized WPML-compatible themes in our directory here: https://wpml.org/documentation/theme-compatibility/
This is the technical support forum for WPML - the multilingual WordPress plugin.
Everyone can read, but only WPML clients can post here. WPML team is replying on the forum 6 days per week, 22 hours per day.