I just had this too - FreePBX Framework Upgrade 14.0.2.16 crashed module admin apparently when it tried to retrieve GPG signatures and then I had to install again, got the tampered file warning, and re-downloaded and installed it, then it was okay. I think something is borked with signature retrieval in the upgrade process.
I had the same issue today. I re-downloaded and forced a reinstall and it cleared up the problem. Seems to me that if we all had the same issue we can’t all be doing something wrong. Maybe something could be wrong with somewhere in the update process?
I just had same problem with latest update/s, and showing 21 tampered files.
fwconsole ma refreshsignatures appears to have resolved all issues.
An update to framework was included in this refreshing process.