Extreme server lag with 1.9 snapshots

[16:57:52 FATAL]: Fatal error launching game. Report this to http://bugs.mojang.com please!
java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:901) ~[?:1.8.0_25]
at java.util.ArrayList$Itr.next(ArrayList.java:851) ~[?:1.8.0_25]
at net.minecraft.launcher.updater.MinecraftVersionManager.getInstalledVersions(MinecraftVersionManager.java:185) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.Launcher.cleanupOrphanedVersions(Launcher.java:431) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.Launcher.performCleanups(Launcher.java:495) ~[launcher.jar:1.6.48]
at net.minecraft.launcher.game.MinecraftGameRunner.launchGame(MinecraftGameRunner.java:231) ~[launcher.jar:1.6.48]
at com.mojang.launcher.game.runner.AbstractGameRunner.onDownloadJobFinished(AbstractGameRunner.java:186) [launcher.jar:1.6.48]
at com.mojang.launcher.updater.download.DownloadJob.popAndDownload(DownloadJob.java:122) [launcher.jar:1.6.48]
at com.mojang.launcher.updater.download.DownloadJob.access$000(DownloadJob.java:12) [launcher.jar:1.6.48]
at com.mojang.launcher.updater.download.DownloadJob$1.run(DownloadJob.java:86) [launcher.jar:1.6.48]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_25]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_25]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_25]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_25]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_25]

This error appears when trying to join a server running snapshot 15w50a, I'm the only member of the server experiencing problems and I can join 1.8.8 servers with no issues. All interactions with mobs/chests/etc are delayed by up to a full minute. Standing in one spot for several minutes allows normal interactions with objects within 10 blocks or so of the player, but moving further out brings lag back. My ping on this server is 198ms.