Unbelievably excited about Scream Factory's upcoming 4K/blu-ray release so I just watched this Q&A.
Apparently James Horner had written a complete score for the film and was all set to record or had just started recording when the musicians strike happened.
"[…] was recording it or finish arranging it and they were beginning to record it, when the composer's union went out on strike, and he couldn't deliver anything because they were on strike. Even though he had a lot of completed pieces available."
The producer of the film wasn't willing to wait, even though there was no release date.