This may have to do with tiles not existing in the ocean. Fetching LODES data for Long Island, for example:
22:35:21.889 [pool-2-thread-3] INFO c.c.data.census.SeamlessSource - Read 167000 features
22:35:21.907 [pool-2-thread-3] INFO c.c.data.census.SeamlessSource - Read 168000 features
Exception in thread "pool-2-thread-3" com.amazonaws.services.s3.model.AmazonS3Exception: The specified key does not exist. (Service: Amazon S3; Status Code: 404; Error Code: NoSuchKey; Request ID: 072F0D38F9BCF756; S3 Extended Request ID: IX34emy8ScvS1eGqydWnm8Vby0JxAbLuEbo0o72q2wJnfLSHcl0720IcZcgDwiq9A39nQ6U7CjA=), S3 Extended Request ID: IX34emy8ScvS1eGqydWnm8Vby0JxAbLuEbo0o72q2wJnfLSHcl0720IcZcgDwiq9A39nQ6U7CjA=
at com.amazonaws.http.AmazonHttpClient$RequestExecutor.handleErrorResponse(AmazonHttpClient.java:1632)
at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeOneRequest(AmazonHttpClient.java:1304)
at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeHelper(AmazonHttpClient.java:1058)
at com.amazonaws.http.AmazonHttpClient$RequestExecutor.doExecute(AmazonHttpClient.java:743)
at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeWithTimer(AmazonHttpClient.java:717)
at com.amazonaws.http.AmazonHttpClient$RequestExecutor.execute(AmazonHttpClient.java:699)
at com.amazonaws.http.AmazonHttpClient$RequestExecutor.access$500(AmazonHttpClient.java:667)
at com.amazonaws.http.AmazonHttpClient$RequestExecutionBuilderImpl.execute(AmazonHttpClient.java:649)
at com.amazonaws.http.AmazonHttpClient.execute(AmazonHttpClient.java:513)
at com.amazonaws.services.s3.AmazonS3Client.invoke(AmazonS3Client.java:4365)
at com.amazonaws.services.s3.AmazonS3Client.invoke(AmazonS3Client.java:4312)
at com.amazonaws.services.s3.AmazonS3Client.getObject(AmazonS3Client.java:1415)
at com.conveyal.taui.grids.SeamlessCensusGridExtractor$S3SeamlessSource.getInputStream(SeamlessCensusGridExtractor.java:40)
at com.conveyal.data.census.SeamlessSource.extract(SeamlessSource.java:71)
at com.conveyal.data.census.SeamlessSource.extract(SeamlessSource.java:41)
at com.conveyal.taui.grids.SeamlessCensusGridExtractor.retrieveAndExtractCensusDataForBounds(SeamlessCensusGridExtractor.java:53)
at com.conveyal.taui.controllers.OpportunityDatasetController.lambda$downloadLODES$3(OpportunityDatasetController.java:119)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
This may have to do with tiles not existing in the ocean. Fetching LODES data for Long Island, for example: