In your demo link (React App), when I click the Get Accounts (or whatever action using the web3 object), it will thow the error:
errors.ts:188 Uncaught (in promise) Error: Expected pubKey to be of length 64
at a (errors.ts:188:10)
at Object.internal (errors.ts:52:45)
at t.sendAsync (INetworkController.ts:125:27)
It happens the same with your example Github in my local environment:
I did some debug and found the coreKitInstance.state.tssPubKey has 65 bytes in lengh but I don’t know it could be the root of this issue or not.
Please take a look and fix it.