[core] Add nullness checking from static analysis

[WinterSolstice8]

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• [x] I understand that if I do not agree to the following points by completing the checkboxes my PR will be ignored.
• [x] I understand I should leave resolving conversations to the LandSandBoat team so that reviewers won't miss what was said.
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• [x] I have tested my code and the things my code has changed since the last commit in the PR and will test after any later commits.

What does this pull request do?

Adds some nullness checking I found in a static code analysis

Steps to test these changes

Test things effected, see no change