I noticed a lot of communities or posts are missing when I view them from my lemmy.ca account vs. the piefed.ca one.
An example would be the technology@piefed.social community.
I can only see around 5 posts from my Piefed.ca account while my Lemmy.ca can see what seems to be all of them.

Ah this totally makes sense. I remember Lemmy having similar issues early on but it became a moot point as time went on and more users began to use it.
Hopefully there is a way to bulk import old posts in the future.
Thanks for the explanation!