i'm not an economist or a game theorist so i don't remember the details but this paper talks about how certain market designs lead to untruthful bidding

https://www.cs.cmu.edu/~sandholm/vickrey.IJEC.pdf

but in the context of second price auctions.

lpage might be alluding to something having to do with their proxy bidder implementation but the above paper actually discusses how proxy bidders themselves lead to untruthful bidding (so maybe lpage is suggesting their implementation is better?).