Child Product - Select a variant

[mclernons]

Joomla 3.6.5
VM 3.0.19.3

Got an intermittent issue.  I'm in the process of creating child products for bulk buys instead of single buys.  I'm populating a "quantity" menu using custom field type "Multi-Variant".  Of the 50 child products so far I've created I've come across this issue.  Sometimes the drop down menu will not update the price of the product.  Deleted the child product, edited the parent to remove the menu.  Saved.  Created a new child product.  Still can't select the child in the drop down menu.  Sometimes it will work, other times it won't

Created a test menu for type "Generic Child Variant"  When I create this drop down menu I get more info.  On that item it now shows "Choose a variant" if it was the 1st item selected.  Otherwise if it was a 2nd selection it will show the 1st item price.

The child product affected is viewable by itself
Current affected product with parent
https://www.mclernons.com.au/hooks-prongs/ap563-250mm-long-pegboard-hook-heavy-duty-pack-of-50
https://www.mclernons.com.au/index.php?option=com_virtuemart&view=productdetails&virtuemart_product_id=2926&Itemid=733