I've also done some spend yesterday and today to get over a level. I asked Amex support and they said

"The transactions needs to be posted on 21 May so that the offer points can be added." and when I queried if that included transaction made today was told "If the transactions is posted on 21 May then it will be counted yes"

Now the transactions from yesterday (and today of course) are all saying 'Pending'. As detailed, I presume that 'Posted' means logged, irrespective of when they are fully processed.