Categories and child categories do not load any time

[jflash]

Hello!
Thank you for great Virtuemart product! I have used it years and i like it (Y)
Now i have strange problem: webpage do not show always categories or subcategories. I go to my site and see first primary categories, but when i select some category webpage refreshes but does not show child categories every time. After i refresh page (F5) it refreshes and shows them... After some trying it does not show again. Sometimes shows, sometimes does not.
I have disabled plugins and components, changed template - same. Where to start? Disabled all caching too. Im going crazy 

Site: https://www.autostuudio.ee
Joomla: 3.10.5
VirtueMart: 3.8.8 10472
PHP:  7.4.28

[jenkinhill]

Console shows a repeating error:
Uncaught ReferenceError: myValidator is not defined
    interval https://www.autostuudio.ee/mootorrataste-lisavarustus:144

Not sure if that is relevant, though.

[jflash]

OK, i made changes in template override file /templates/bestshop/html/com_virtuemart/category/default.php and disabled lines. Now all OK, maybe this template code too old.

// Show child categories
//if ($this->showcategory and empty($this->keyword)) {
//   if (!empty($this->category->haschildren)) {
      echo ShopFunctionsF::renderVmSubLayout('categories',array('categories'=>$this->category->children));
//   }
//}