Hey Team, good morning.
I use Joomla! 2.5.9 Virtuemart 2.0.20b.

I will try to give all details for you to check, that it really does not work:
1) Create new custom field 'Plug-ins' - 'Stockable variant'. Add few values.
2) In Configuration in part 'Action when a Product is Out of Stock' choose 'Displays 'Notify Me' instead of 'Add To Cart' button'
3) Create product.
4) Create 2 childs to it.
5) Set 'In stock' of childs to 1.
6) Now try to order 1 item of child product.
7) Then return to product and order 1 item of same child again.
What happend? Yes, you have added same item again to cart (already twice), while there are only one item shall be available.

Can you help me with this issue? PureMart fixes this bug?

Thanks in advance!

Hi , sorry for the delay in answering

first please check without our template - it is after all only a template..
Please can you test with Puremart completely disabled.
To do this just rename the folder

ROOT/templates/YOUR_TEMPLATE/html/com_virtuemart

to

ROOT/templates/YOUR_TEMPLATE/html/com_virtuemart2

if your using over-rides set them off as well in Configuration->Templates

if the bug is still present then please post at the VM forums..

if not we will have a look..

Cheers