No changes made on parent item

[valir]

Good day!

The problem is:
I have product with 26 childs. All goes well and suddenly this parent product could not be modified!!!
Click on Save&Close, Save, even just Close action goes to VirtueMart Control Panel (/administrator/index.php?option=com_virtuemart&view=virtuemart)

There are other parent products with childs but this happens only for One with 26 childs

I need your help

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I unpublish this item (using action in product list) and now when I save modifications I see "Invalid Token save" on White Background.
What is wrong?
Please help

[valir]

There is limit of memory for your script execution!