We are building templates for Virtuemart. We are not the developers of Virtuemart Component itself. The problem you have experienced is 100% related to Virtuemart Core. We can't release a patch for it, even if we want to, because we are not allowed to touch the vm core files as template developers.
Check forum.virtuemart.net/ in case anybody raise this issue before you, or in the worse case, request this patch from VM developers, so it will be fixed in the upcoming VM release.
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