Trying to open some chests in underwater ruins and shipwrecks crashes server

Trying to open certain chests in underwater ruins and shipwrecks crashes a multiplayer server, with the error "java.lang.OutOfMemoryError: Java heap space". Bug was found to affect more than one player. Client-side, it appears that the chest is opened, but is empty. Likely something to do with trying to generate Explorer Maps?

Console log:

11.06 00:29:28 [Server] INFO at cfp.a(SourceFile:39) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at cfn.b(SourceFile:67) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at cfn.a(SourceFile:55) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at cfm.a(SourceFile:32) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at cfw.a(SourceFile:56) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at sm.a(SourceFile:1048) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at sl.a(SourceFile:308) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at bqc.a(SourceFile:76) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at bwm.a(SourceFile:150) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at bwm.a(SourceFile:222) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at sl.d(SourceFile:143) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at agk.c(SourceFile:90) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at tg.a(SourceFile:25) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at tg.a(SourceFile:50) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at java.util.Map.computeIfAbsent(Unknown Source) ~[?:1.8.0_152]
11.06 00:29:28 [Server] INFO at tg$$Lambda$1449/99235188.apply(Unknown Source) ~[?:?]
11.06 00:29:28 [Server] INFO at tg.a(SourceFile:51) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at tg.a(SourceFile:70) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at bqx.b(SourceFile:135) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at bqx.a(SourceFile:83) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at bqx.b(SourceFile:93) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at hh.a(SourceFile:80) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at hh.a(SourceFile:84) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at hh.a(SourceFile:119) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at gx.a(SourceFile:82) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at gx.a(SourceFile:448) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at gx.a(SourceFile:82) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at gx.a(SourceFile:448) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at hd.a(SourceFile:69) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at gx.a(SourceFile:82) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at gx.a(SourceFile:448) ~[server.jar:?]
11.06 00:29:28 [Server] INFO at gu.a(SourceFile:56) ~[server.jar:?]
11.06 00:29:28 [Server] INFO Caused by: java.lang.OutOfMemoryError: Java heap space
11.06 00:29:28 [Server] INFO at java.lang.Thread.run(Unknown Source) [?:1.8.0_152]
11.06 00:29:28 [Server] INFO at net.minecraft.server.MinecraftServer.run(SourceFile:531) [server.jar:?]
11.06 00:29:28 [Server] INFO at net.minecraft.server.MinecraftServer.v(SourceFile:626) [server.jar:?]
11.06 00:29:28 [Server] INFO at rx.w(SourceFile:365) [server.jar:?]
11.06 00:29:28 [Server] INFO at net.minecraft.server.MinecraftServer.w(SourceFile:670) [server.jar:?]
11.06 00:29:28 [Server] INFO at k.a(SourceFile:149) [server.jar:?]
11.06 00:29:28 [Server] INFO at java.util.concurrent.FutureTask.get(Unknown Source) ~[?:1.8.0_152]
11.06 00:29:28 [Server] INFO at java.util.concurrent.FutureTask.report(Unknown Source) ~[?:1.8.0_152]
11.06 00:29:28 [Server] INFO java.util.concurrent.ExecutionException: java.lang.OutOfMemoryError: Java heap space
11.06 00:29:28 [Server] Server thread/FATAL Error executing task