Do not try to access vector items if (re)allocation failed

[DL6ER]

What does this implement/fix?

Triggered by #2078 and #2079. Even though it may not be the final solution returning an error when no memory could be allocated is still a useful thing to do rather than proceeding anyway and (most likely) ending up in a crash.

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Related issue or feature (if applicable): N/A

Pull request in docs with documentation (if applicable): N/A

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