Earning points on base miles is and always has been part of the terms and conditions of the program. I can't speak for other airlines, but American has the same restriction, so it wouldn't surprise me if this is standard. Points cost money, and giving points on pass throughs that don't earn any revenue for an airline doesn't make sense.
From aa.com, but emphasis mine:
Which AAdvantage® miles don’t count toward earning Loyalty Points?Expand- Bonus miles earned from special promotions
- Miles from Buy, Gift, Transfer transactions
- Government taxes, fees, and other charges associated with buying a ticket do not count toward earning AAdvantage® miles and do not count toward earning Loyalty Points
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