vercel: Builds failing, but only indication is dashboard 'error' badge

Using next@5.1 with typescript@2.8 and now@11.0.7 (have also tried now@12.0.0-canary.5)

The branch builds and runs locally (win 10, node 9 using bash for windows) in ~120 seconds with no errors.

However, when deploying to now, the build hangs indefinitely on next build.

The only indication that something’s gone wrong is in the now.sh dashboard, where the big red “ERROR” badge appears (usually within the first few minutes of deploying):

But the logs show no error (these are from now.sh, but they basically mirror my terminal):

04/09 11:43 PM (4m) install
04/09 11:43 PM (4m) ✓ Using "yarn.lock"
04/09 11:43 PM (4m) ⧗ Installing 89 main dependencies…
04/09 11:43 PM (4m) npm run build

note that my build script is simply NODE_ENV=production next build

But, when I switch to my master branch and deploy, however, it builds fine. There aren’t any architectual differences b/t the two branches (just a new route and some new components), so the build process is about the same.

So, I assume it’s gotta be something in my code that’s breaking the build, but I can’t figure out why:

(a) it builds locally just fine or (b) there’s no error message at all

Is there anyway to debug this? or maybe more detailed logs available server-side? now should be printing some indication as to why it’s failing, right?