It might happen, but usually if they have an email, they process via email. If you got anything before via email, it should continue to be sent by email. But, you know, there is sometimes a glitch in their system... but that's nothing to worry about.
In my case, when we reached 16 months (expected timeline for SA and AIP when we applied), I ordered our GCMS notes and found out they did a typo on my email. When I called, they told me they realised the email wasn't valid so my communications were set by regular mail. I sent a case-specific enquiry to correct the typo they made (and I know it's their mistake, because I had kept a copy of everything I sent them). Few months later, I got my SA via email.