Do you happen to know why he wouldn’t have executed the options before this suit?

It's Elon. There are a wealth of possible reasons, ranging from actually reasonable to 'it sounded better in my head'.

One possibility is that he may have been attempting he usual market manipulation shenanigans; wherever he publicly goes in the market, he is followed by millions of worshipping fanboys.

He could also be thinking the price would plummet below the contract price (or that he could make it do so then raise it again).

Or maybe he didn't like the fact that he'd have to hold them for 5 years before being able to do what he wanted with. Elon is not known to simply abide by trading regulations.

Maybe he wanted a tax write off?

Or he could have simply forgot. This is Elon, after all.