I did summer school for 3/4 years of university, I was full-time during the normal Fall/Winter school year, but if summer school counts as part-time studies, then I am kinda screwed lol
You are allowed to work full time in regularly scheduled break even on a part time load if you have been full time before and after that break term.
The basic premises of PGWP is that you should be full time student in all the terms except last term .The PGWP requirements are generally silent on your facts.
Students have been taking courses while doing a coop term without any prejudice .
My personal opinion is that Since you have not violated the basic full time status of a study permit you should be fine.
Take precaution to get a letter from your institution clearly stating that you took courses in a regularly scheduled break. Clearly state in your explanation that you were full time in all your academic terms and took additional courses in regularly schedule break. Alternatively the school will not refuse you the letter stating that summer term of all the years are regularly scheduled break.
Just search these threads and find out people who were in your situation and pm them.
'They have maintained full-time student status in Canada during each academic session of the program or programs of study they have completed and submitted as part of their post-graduation work permit application.'
The key word is Academic session. As long as you have letter stating that summers are regular breaks ( implying non-academic session ) you should be fine
