This problem applies to VM which has been cloned from the other one.
When trying to StorageLiveMigrate cloned VM through WebUI I get the following error:

Error "Invalid value: "migrate-storage-class/restore-02d5825a-347a-4d36-b400-3e109d1f3ccc-rootdisk-mig-qoxfun": name part must be no more than 63 characters" for field "metadata.annotations".

I believe WebUI should ensure it does not make any operation that would exceed well known and well established limits in regard to lenght of any object fields ;-)

OCP 4.18.4
kubevirt-hyperconverged-operator.v4.18.0

1. Using WebUI create a VM - name it "f"
2. Using WebUI create a clone of that VM - name it "f2"
3. Using WebUI make an attempt to StorageLiveMigrate the clone (f2) VM - WebUI will throw the error:

Error "Invalid value: "migrate-storage-class/restore-02d5825a-347a-4d36-b400-3e109d1f3ccc-rootdisk-mig-qoxfun": name part must be no more than 63 characters" for field "metadata.annotations".