According to Foresight News , DEX aggregation protocol 0x released a report alleging systemic price fraud by some propAMMs on the Base network. The investigation found that these operators exploited Base's Flashblock architecture, posting highly attractive prices in the final 200 milliseconds before the end of a block (the last Flashblock) to entice aggregators to route their orders, only to immediately adjust the prices at the start of the next block. This behavior typically results in traders incurring additional losses of 5 to 10 basis points. Based on a monthly trading volume of $1 billion, this could mean a single liquidity source could cause users to lose an additional $500,000 per month.
Furthermore, the report also points out that some operators maliciously widen interest rate spreads by exploiting the delay between pricing and settlement, or manipulate LP rewards through "phantom liquidity," which involves depositing large amounts of liquidity before the end of a block and then quickly withdrawing it at the start of the next block. This can cause aggregators to guide users onto paths with higher slippage due to incorrect depth data. 0x states that it currently integrates 5 propAMMs on the Base network, but will protect users by continuously monitoring execution quality and cutting off sources of illicit liquidity.
