As with the previous ticket MC-215510, I was able to extract only the vanilla files and the specific regions (r.-2.0.mca and r.-1.0.mca) to recreate the crash issue. There were no additional packs or plugins used to change block behaviour or introduce additional blocks.

It occurs if one player logs in at or teleports to the position -606 67 234.

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The crash log is attached, a short excerpt follows:

Description: Exception ticking world

java.util.ConcurrentModificationException
at java.base/java.util.HashMap$HashIterator.nextNode(HashMap.java:1584)
at java.base/java.util.HashMap$KeyIterator.next(HashMap.java:1607)
at aag.a(SourceFile:1007)
at brx.a(SourceFile:251)
at brx.a(SourceFile:217)
at brx.a(SourceFile:291)
at cea.a(SourceFile:232)
at ceg$a.a(SourceFile:835)
at aag.a(SourceFile:1064)
at aag.ak(SourceFile:1055)
at aag.a(SourceFile:366)
at net.minecraft.server.MinecraftServer.b(SourceFile:871)
at zg.b(SourceFile:312)
at net.minecraft.server.MinecraftServer.a(SourceFile:811)
at net.minecraft.server.MinecraftServer.w(SourceFile:670)
at net.minecraft.server.MinecraftServer.a(SourceFile:257)
at java.base/java.lang.Thread.run(Thread.java:832)

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The server files can be found here:
https://mega.nz/file/6x8ETAZL#ZV9SLor0RPbHXD2F5xxhwVjZNUm3ac6ItZYKLWon_VQ