I think the bump since IPO can be explained at least partially by low float not meeting demand. I've seen a lot of accounts from retail investors who entered the lotteries saying they only got a small fraction of what they wanted, hence demand is kept artificially high. Probably intentionally, since it essentially allows the optimists to dictate the price.

(edit: This is not at all unique to spacex, of course, but given the nature of Musk's companies and their "fans" it's logical that they would employ this strategy. They are also doing a staggered unlock to avoid upsetting the market when insiders start dumping their shares.)

"investors" really over-sells who these people are. They're people with gambling apps on their phones who think SpaceX is great because of Musk's politics.