After copying a VBK and VBM file from one server to another , after a test restore the following error showed up in the logs and in Gui
Storage version [3701403] is not supported for read-only access.
--tr:Failed to open storage for read access. Storage: [\\path\to\file.vbk].
--tr:Cannot apply patches stored in folder [HostFS://\\path\to\file.vb[41e6829d-533e-480f-8b38-3726d3fa47a2 (vm-4628)]]
--tr:Failed to build restore point.
After my own research ( Trying to copy it locally ) and contacting Veeam support , it turns out the VBK file was corrupt some how. Recopying the file resolved this issue