I can’t see your full code but is ‘t’ defined? Typically how I’ve seen card-button callbacks is that they take a ‘t’, and use that to call the client library. It seems like you are trying to use the client library from two sources, a ‘t’ and a ‘context’. Perhaps your issue lies there?
Also, your console shows the stack trace error with something in your client.js:63:29? I can’t see your code but perhaps that line is related somehow?