hmr logs out NaNms on first load

[damiensedgwick]

Link to the code that reproduces this issue

https://github.com/damiensedgwick/hmr-nan-repro

To Reproduce

1. Start the development server
2. Open the devtools on your chosen browser
3. Visit localhost
4. On first load, the hmr module will report that it took NaNms

Current vs. Expected behavior

Currently displays NaNms

I would expect that if latencyMs is not a number, that it should not be logged out.

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.4.0: Fri Apr 11 18:32:50 PDT 2025; root:xnu-11417.101.15~117/RELEASE_ARM64_T6041
  Available memory (MB): 24576
  Available CPU cores: 12
Binaries:
  Node: 22.14.0
  npm: 10.9.2
  Yarn: N/A
  pnpm: 10.10.0
Relevant Packages:
  next: 15.3.2 // Latest available version is detected (15.3.2).
  eslint-config-next: 15.3.2
  react: 19.1.0
  react-dom: 19.1.0
  typescript: 5.8.3
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Not sure

Which stage(s) are affected? (Select all that apply)

next dev (local)

Additional context

No response