Starwood Preferred Guest - AE card, not 1:1 earning?

Recently I noticed that my Starwood AE doesn't earn the same amount of Starpoints. SPG.com posted only about 65% worth of my payment this month and 90% last month. I do not have financial charges / fees / advances....etc, in these balances, and I alway paid in full. What would be the cause?

I read the T&C on AE website -
Use your Starwood Preferred Guest Credit Card wherever American Express® Cards are accepted and you’ll earn one Starpoint for every eligible dollar you spend.1
1. Eligible spending includes purchases of goods or services, when purchases have not been returned or otherwise rescinded, and are not subject to a credit; it does NOT include fees, Finance Charges, Cash Advances, Balance Transfers, or adjustments to your account.

What did I miss?

It is very much a 1:1 program.

The only time I've ever seen my count differ from the actual number of dollars billed in a cycle has been when there have been credits issued from the previous billing cycle or some other non-usual billing circumstance.

It threw me the first time I encountered it, but a careful review of the bill made it clear.

Perhaps you have similar? If not, a quick call to AMEX should clear things up.