Server: git-Spigot-8faa8b4-13ed05d (MC: 1.15.2)
Prism: v2.1.5-106

An error occurred in the following operation.

/pr wand rollback
Specify the location of the destroyed powered_rail (off).

[17:22:46] [Server thread/INFO]: [Prism]: Applier error: Material must be a block!
[17:22:46] [Server thread/WARN]: java.lang.IllegalArgumentException: Material must be a block!
[17:22:46] [Server thread/WARN]: at com.google.common.base.Preconditions.checkArgument(Preconditions.java:122)
[17:22:46] [Server thread/WARN]: at org.bukkit.craftbukkit.v1_15_R1.block.CraftBlockState.setType(CraftBlockState.java:133)
[17:22:46] [Server thread/WARN]: at me.botsko.prism.actions.BlockAction.placeBlock(BlockAction.java:382)
[17:22:46] [Server thread/WARN]: at me.botsko.prism.actions.BlockAction.applyRollback(BlockAction.java:270)
[17:22:46] [Server thread/WARN]: at me.botsko.prism.appliers.Preview.lambda$processWorldChanges$0(Preview.java:299)
[17:22:46] [Server thread/WARN]: at org.bukkit.craftbukkit.v1_15_R1.scheduler.CraftTask.run(CraftTask.java:81)
[17:22:46] [Server thread/WARN]: at org.bukkit.craftbukkit.v1_15_R1.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:394)
[17:22:46] [Server thread/WARN]: at net.minecraft.server.v1_15_R1.MinecraftServer.b(MinecraftServer.java:1036)
[17:22:46] [Server thread/WARN]: at net.minecraft.server.v1_15_R1.DedicatedServer.b(DedicatedServer.java:406)
[17:22:46] [Server thread/WARN]: at net.minecraft.server.v1_15_R1.MinecraftServer.a(MinecraftServer.java:984)
[17:22:46] [Server thread/WARN]: at net.minecraft.server.v1_15_R1.MinecraftServer.run(MinecraftServer.java:824)
[17:22:46] [Server thread/WARN]: at java.lang.Thread.run(Thread.java:748)

Please use the development release here
https://jenkins.addstar.com.au/job/Prism-Bukkit/

I could not replicate the fault. That being said I do believe "wand" rollbacks are consistent and I would not use them

I tested with the following

1. Placed 3 powered rails - and placed a torch to power 1 of them.
   2, broke all 3 rails
2. Ran pr l a:break t:1m and confirmed it showed the three breaks.

[20:45:54] [Render thread/INFO]: [CHAT] Prism // Showing 2 results. Page 1 of 1
[20:45:54] [Render thread/INFO]: [CHAT]  - [1] Narimm broke powered rail x2 just now (a:break)
[20:45:54] [Render thread/INFO]: [CHAT]  - [2] Narimm broke powered rail just now (a:break)

4. Ran pr rb a;break t:5m

[20:49:36] [Render thread/INFO]: [CHAT] Prism // Preparing results...
[20:49:36] [Render thread/INFO]: [CHAT] Prism // Beginning rollback...
[20:49:36] [Render thread/INFO]: [CHAT] [!] rollback by Narimm r:1 a:break t:5m -extended
[20:49:36] [Render thread/INFO]: [CHAT] Prism // 3 reversals. It's like it never happened.

Could not replicate.

If the break occured prior to 1.15 then it will probably fail. Other than that I would need to see the db line entry

No response - Please try the latest builds and open a new issue if its still happening