getAnswer will take a roundId input for BASE_AGGREGATOR to get a round-specific price. However, it only takes the latest price for WEETH_AGGREGATOR. Since both prices will be used in convertWEETHPrice, this means when the roundId doesnt correspond to the latest answer round as defined in WEETH_AGGREGATOR. The resulting eETH price is invalid.
Note: same issue in getRoundata(). There are no checks to ensure the input _roundId matches WEETH_AGGREGATOR.latestAnswer().
Invalid price whenever roundId doesnt correspond to latest round as defined in WETH_AGGREGATOR.
Currently, getAnswer and getRoundata are not embedded in any flow, so no material impact for now. But as a helper function, the implementation will mostly result in an invalid price.
Note: similar issue in SUSDSPriceAdapter.sol. No check to ensure roundIds price is corresponding to the conversion rate from RATE_PROVIDER. 
Since each pricefeed has its own roundId increment threshold and intervals, a roundId from two different priceFeeds most likely not the same. Fetching historical data involves searching for roundIds in both aggregator that overlaps in time. If there is a need for historical data search, consider searching based on a timestamp instead of a roundID.
If there is no need for historical data search, consider only provide methods for latest price.
