Sometimes this circuit is used for products that work with both 120VAC and 240VAC.
Drawn like this it would double the output voltage, but when you break the link between TP+ and AC- it would act as a full bridge rectifier for 240V (or 230V really) countries. Although for use with 230V there should be resistors across both the caps to balance out the leakage current.
That might be where the mistake comes from, it's not an uncommon thing to see in various products as I understand it.