Mixing up "lifetime" and "life"

There seems to be a recent, I'm guessing post-Millennial but maybe Millennial, shift toward using "lifetime" when we mean "life". So far I only hear it in American-English YouTube.

Google AI explains the difference this way:
> ... they differ slightly in scope.
> "In my life" refers to your entire existence up to the present moment.
"In my lifetime" encompasses all the years you will ever live, often looking back on a historical era or a span of time that is drawing to a close.

It's most often after a superlative adjective, but not always (best in my lifetime, etc.)
I don't think the reverse ever happens. I never hear anything like "It's a once-in-a-life opportunity".

Examples:
- But it's limited to just two times in your **lifetime**.

No source file, test, or entry point is identified in the issue. Start by reviewing Harper's existing grammar rules and tests for word-choice distinctions, then determine whether the examples support a precise rule and add coverage for the reported lifetime usage.

Written by the indexing model from the issue text.