The runtime console logs aren’t necessarily related to build success or failure.
They’re also formatted as production errors, so they’re obfuscated.
As it instructions you would have needed to run your dev environment to see the real error.
It wouldn’t have mattered, but I cannot due to the site having been removed.
If I’m interpreting this correctly you’re saying:
“It doesn’t work correctly at runtime because it needs the GSAP plugin and doesn’t have it”
Then separately:
“When I add the GSAP plugin the build fails”
Perhaps you’re right, I don’t know enough about specifically what you’re working with.
However I’m just pointing out that the build error as reported doesn’t mention the plugin at all.
It mentions only a SyntaxError in .next/server/pages/About.js
This doesn’t surprise me, because you probably checked a ‘source file’ of some kind.
However the error seems to indicate line 11 position 5426, so is likely to be a minified output file.