My point is that using "grokking" in ML is not a Musk/Twitter/Whatever-his-Ai-company-is-named invention, it predates their use.

Yes the original researchers reused a pre-existing meaning, which has been in internet for a while before. I did not know it came from Heinlein and I did not know its full meaning. I remember seeing it first, more than a decade ago, in a text that explained without any explanation that an isolated unknown word can easily be groked from context. Demonstrating it immediately. To me (and I guess to those researchers) "grok" means "understanding from context" which is particularly appropriate in the context.

BTW Elon was not the only one to reuse this word. Another company named Groq, totally unrelated to Musk as far as I know, designs AI acceleration chips.