I have found that the backend code of the master branch also has this problem, but I have not tested the latest version for this problem.
I saw that there was no corresponding release branch for the historical version, so I modified the pr based on v2.6.1 on a new branch, and the new branch name was v2.6.1-patch

I tested this issue with postman in release-7.10.0 and the problem persisted.
The test API body is as follows:
{"name":"","namespace":"_all","content":"apiVersion: k8s.tmlake.com/v1\nkind: VirtualServer\nmetadata:\n name: test-vs-http\nspec:\n resourceClassName: dev1\n partitionName: k8s-adc\n name: httpvs\n ipType: ipv4\n vip: 0.0.0.0:456\n httpProfileName: test-hp\n aclProfileName: test-ap\n enable: \"on\"\n protocol: smart-http\n natName: [\"default\", \"n1\"]\n natRules:\n - name: n1\n desc: \"n1 desc\"\n - name: n2\n desc: \"n2 desc\"\n toSrcType: ip_pool\n ipPool:\n method: conn_rr\n bindingVlanName: vlan_ha\n snatIp:\n - 192.168.80.1-192.168.80.255\n - 192.168.56.1-192.168.56.255\n snatIpv6:\n - fe80::2291:1dcc:1ccb:f5ea-fe80::2291:1dcc:1ccb:ffff\n srcVlan:\n - vlanName: vlan_ha\n - vlanName: vlan_192\n - vlanName: vlan_172\n pool:\n name: tcppool\n service: productpage\n portNumber: 9080\n lb: rr\n\n","validate":true}

Set namespace to "_all", and do not set the namespace field for content.metadata

so I modified the pr based on 7.10.0 on a new branch, and the new branch name was 7.10.0-patch.