Hi Herman,
I took a closer look at the issue and finally discovered what was interfering with the WooCommerce translations in certain themes, like Astra. From the WordPress customizer under: WooCommerce / Cart, there was an option enabled that added the phrase “BUY NOW” to the cart button. I’m not used to this option being enabled by default, but apparently this has changed in a recent update.
Thanks anyway.
The first thing I did was to explain the problem in the plugin forum, because the only problem I had in my installation of WordPress has been with that plugin, but today nobody has answered anything…