Watchify + tsify + Visual Studio == stale code

Question

We are running a Gulp task inside of Visual Studio (2015) to execute watchify. Works great some of the time, but sometimes watchify builds old code.

Repro:

• Modify a .ts file in Visual Studio
• Save
• In the Task Runner Explorer, watch for watchify output, indicating that it ran (it does)
• Refresh Chrome/clear cache (I use the "disable caching while debug window is open" option in Chrome)
• View source in the Chrome Debugger (a little less than half the time, it will be the old code)

Any idea what I need to look for? Note that if I execute a full browserify build, Chrome always sees the new code -- this staleness problem only happens when Watchify is in the mix.