Thanks for asking.
I see that you are using the latest supported version of WooCommerce but website is having old version of Pro Theme which might cause compatibility issues. In that regards, I suggest you to update Pro Theme to latest version which as of today is 2.3.8. Upon updating, please make sure to clear cache and then load the website and test the product page tabs on mobile.
To update Pro Theme please take a look at following resources:
Version compatibility guide: To learn about the latest and compatible versions of bundled and supported plugins, please take a look at following doc:
2. Theme Update guide: Please take a look at following article to update Pro Theme.
3. Please take a look at following doc about changelog: