MusicVAE.interpolate() throws an error when inteprolating 4 sequences inside Web Workers

[HenriAugusto]

Hi!

I've was trying to interpolating between 4 sequences with MusicVAE inside a dedicated workers and got an error.

Steps to reproduce:

1. Create a Worker:
2. Create a MusicVAE instance¹
3. Call .interpolate() with an array of 4 note sequences.

¹ tested with two checkpoints: one, two

I've attached an example project with a MCVE: Magenta Issue 578 - Bug MCVE.zip

Note the relevant lines inside main.js and worker.js are identical.

My console output on MS EDGE:

[HenriAugusto]

It is related to tfjs.

Works with tfjs 2.8.6.
Doesn't with tfjs 3.0.0