Their interview is a parody of FAANG loops:

• Some interviewers do not even introduce themselves.
• There is no code editor; they copy and paste code into a shared Google Sheet.
• Assignments lack introductions or descriptions; you are expected to deduce their requirements by reading poorly written code.
• There are no metrics (e.g., solution time/memory complexity, number of requirements addressed) as there is no clear beginning or end to the session, leading to an extremely opinion-based assessment.
• You may be asked about concurrency by someone who has no idea about CAS instructions and does not understand the concept of non-blocking collections.

tl;dr: It's a waste of time for an experienced engineer.

Some notes:

• If you did not come from the Java world, you are a second-class citizen.
• Check the salary range online carefully; if they promised you above, you will most likely be down-leveled after the interview.
• Do not expect constructive feedback as there are no metrics in their interview tasks.

To the Canva interviewers: The purpose of the loop interview at FAANG companies is to reduce the subjective component when making hire/no-hire decisions. What the purpose of the loop interview at Canva is remains an open question to me.

Q: What concurrent collections do you know?