No other file would have that information. Let me just summarize -
1. Files copied from another computer seem to have lost connection with their template.
2. New files created from the same template behave as expected.
3. These templates are visible in the DW Assets panel.
4. Deleting the cache file made no difference in this behavior.
Is that correct?
Do the templates involved validate when tested at http://validator.w3.org?