Multivariant bug in vm 3.0.18

[panagiotiss]

Hi all,

I have updated my site to vm 3.0.18(moreover i tested it in a new fresh installation VirtueMart3.0.18_Joomla_3.6.2-Stable-Full_Package.zip) and i have problems with multi variants custom fields
When you try to insert a new multi variant custom field with 2 Ramification and then try to add child product  a strange value 1213 --> scalar is appeared [see screen1]

after that if you try to configure product childs the following error appears

Error
vmError: VmTable #__virtuemart_products_en_gb Check not passed. Neither slug nor obligatory value at product_name for auto slug creation is given 0
vmError: You are not an administrator or the correct vendor, storing of product cancelled

see screen2

[mkilkie]

I have just added a post with exactly the same content. I thought I had done something wrong.

Also just noticed that when I add a new product it actually adds two new products!

[habashynn]

I have the same issue/bug as well!!!
A work around i discovered is to deactivate/unpublish the created multi-variant (under Custom Fields) then go to the desired product (from the Products menu on the left) use [Add a Child Product] button which is located under "Product Information" tab to add all the product children first -- then back to the multi-variant from Custom Field menu to publish it again... And finally back to the product page BUT this time go to the "Custom Field" tab -- and choose your active multi-varient custom field type from the dropdown menu...
You should see all children appeared below it without those extra bugged lines!
[IMPORTANT: DONOT USE "Add a Child Product" BUTTON WHICH IS LOCATED UNDER THE PRODUCT "Custom Field" TAB]
Modify all children as needed then save -- you shouldn't receive any errors then.

in another say: creating all children before activating the multi-variant is what worked for me!
Hope this bug is being resolved!