Flex 2.16.0 throws errors when accepting a task

[stephenhand]

Description

Since upgrading to Flex v2.16.0 there are new errors being thrown when accepting a new task in Flex

The same error is thrown when wrapping / completing a task.

The errors appear to be non fatal, the website continues operating as normal

Steps To Reproduce

1. Open a legacy webchat session
2. Open a Flex session
3. Set the flex worker 'Available'
4. Complete the webchat form and chatbot
5. Accept the new task in Flex

Expected behavior

The task is accepted without an error being thrown

Actual behavior

An user visible error is thrown,

Additional context

The branch with Flex v2.16.0 has already been deployed to the AS Development Environment for testing