Hello,
This behavior usually happens when the size guide content is added manually through a custom tab. In that case, the content remains the same across all products, even if different size guides are selected in product settings.
Navigate to Products > Custom Tabs > Edit with Elementor, then update the content and set the correct display conditions for products/categories where each size guide should appear.
https://postimg.cc/GBDPTSDK
Alternatively, you can use the WoodMart Size Guide widget in the single product layout, which is designed to work dynamically with per-product and category assignments as a pop-up/trigger
This widget will correctly respect the “Choose size guide” option set for each product.
See Screenshot for better understanding: https://ibb.co/NTT77H9
Best Regards