Minimum reproducible wikitext:

<score vorbis="1">
{a}
</score>
[[File:Example.ogg]]

I can reproduce anywhere with that code.

The issue has also been reported on itwiki.

Somehow, the same code works here but here doesn't

Somehow, the same code works here but here doesn't

That's because of T295514: Score audio uses different players depending on whether the page has other embedded media.

In T363630#9750975, @Nardog wrote:

Somehow, the same code works here but here doesn't

That's because of T295514: Score audio uses different players depending on whether the page has other embedded media.

That task only reports inconsistent behaviour. The indeterminate progress bar issue is occurring in that example.

I was just explaining why it works in your first example and it doesn't in the latter. The presence of other embedded media on the same page triggers the use of the VideoJS player for Score-generated audio.