I know this topic is debated a lot but I feel like cic has changed information on the website and made it clear that you can keep working under your implied status while you're waiting, including IEC.
Source:
https://www.canada.ca/en/immigration-refugees-citizenship/services/work-canada/iec/extend-change.html
"Option 2:
Apply for another
type of work permit.
If you apply for a new work permit, you should submit your application at least 30 days before your International Experience Canada work permit expires. This will ensure that you don’t lose
legal status in Canada.
If your work permit expires before we process your application, you can keep working in Canada until you receive a decision on your application. This is known as
implied status."
Source 2:
http://www.cic.gc.ca/english/helpcentre/answer.asp?qnum=1476
also this one mentions IEC specifically (can't work only if you applied AFTER, so if before...
"Who doesn’t have implied status
You don’t have implied status if you:
- apply to extend your IEC participation after your work permit expires
- you must stop working on the day your work permit expires"