Conditional content based on WooCommerce product stock quantity worked correctly in the default language but failed in translated pages. In the translation, either both buttons appeared or no buttons were visible because the conditional logic could not evaluate the stock value correctly.
Solution:
The stock quantity was not synchronized or set for the translated WooCommerce products. Toolset conditionals evaluate the stock value per language, so the translated products also needed a valid stock quantity. After adding or syncing the correct stock values in the translated products, the conditional display worked as expected.