While somewhat OT, good VU analog meters are simply hard to find. The last ones I used were plastic and needed a custom glass bezel to protect them. I looked again today and no real change. With supply chain issues, they are seemingly not a priority. Many legacy products that have VU meters are often too expensive to consider retrofitting with new amplification.
As for more on topic news, as
@Buckeye Amps reported, the distortion rise is reproducible by those closest to the situation. The challenge has been validating potential remediation as the designer has had test equipment issues. As many know, supply chain issues have hampered test equipment availability too. The designer has had to consider alternative test equipment and, along with personal priorities, progress has been slower than expected. He is pursuing multiple potential solutions and expects to have resolved very soon. Stay tuned and will update as soon as we can!