Issue in cast_receiver.js prevents Custom Chromecast Receiver from running on Chromecast fw 1.26

Question

As the title suggests, since the FW update, i'm getting a very strange error with my Custom Chromecast Receiver.

Uncaught TypeError: Cannot read property 'decrypt' of undefined
    at cast_receiver.js:130
    at cast_receiver.js:236

Basically what happens is that when a user tries to connect to the chromecast device from the client app, my implementation of the Receiver gets this error and will not load, instead the Chromecast goes back to the idle screen.

What's even more interesting is that I have 2 variants of the receiver. Both have the same codebase, but they are hosted in different places. One is hosted on firebase, while the other is hosted on a private server. Both of them worked on the 1.25 FW and now only the one hosted on Firebase works.

I'm trying to understand the error that i'm getting as that's my only lead so far in debugging this issue.

I also saw that several other persons are reporting issues with this latest Chromecast FW, but so far there is no solid response as to why they are having problems. (Source)

Does anyone have an idea as to why this is happening ?

Thanks