Why is the output of a call to the_excerpt different when the call seems to be identical?

by

The only thing date related in that code is $postedon_data. If these are the files being used as you say then there are a few possibilities.

  1. Those unspoken_postedon_* values are set in one case and not set in another.
  2. The unspoken_posted_on function is defined in one case and not another.
  3. There is something about the unspoken_posted_on function that filters what content it displays based on template or other value.

Those are the only options that come to mind. I suspect the last one.

If you can’t work out which it is, var_dump($postedon_data) for both cases and edit the output into the question, and post the content of the unspoken_posted_on` function.