If I understand you correctly, you didn't make a mistake with the number of days absent from Canada, you just forgot to mention that during that trip to India, you also went to SA.
That is not a big deal, however I would suggest that once you received AOR, you submit a CSE to let them know. Be very careful to make clear in the web form that there is NO mistake in the number of days absent, just that one destination wasn't mentioned.
As @spyfy correctly opined - it's not that big of a deal. Just update CPC after your AOR. I'd also add that even if those 8 days of KSA were beyond the 45 days of India ~ still update your CPC by submitting a new Physical Presence Calculator with a letter explaining the oversight.
When filling physical presence calculator, as per instructions, if you visited more than one country, write the last destination in the To country and mention other countries in the notes.
Just send a webform immediately after getting AOR. You'll be fine.
When it comes to Immigration, it's better to provide all the information.
People generally get their citizenship very easily even when they forget a complete trip (not the case here) if clearly above the 1095 threshold.
OP will be fine.
This is why it’s advisable, for those who travel even a few times, to have several physical presence days as a buffer. Sometimes waiting couple months after eligibility to apply could save you all kinds of eventual headaches.
