Background of the issue:
I was translating our shop page to Croatian language using WPML. I added the language normally, and WooCommerce was almost all auto-translated to Croatian. I tried to translate some missing terms via 'String translation'.
Symptoms:
WooCommerce language reverted to all English after adding string translations.
Questions:
How can I prevent WooCommerce from reverting to English after adding string translations?
Why does this issue occur when translating missing terms via 'String translation'?
I followed the same steps that you showed in the video, and the issue did not happen anymore. Can you please verify on your side, if everything is working as expected?
If not, please tell me the steps you took to test it and what was the result.