A small error that occurs when restarting the server. It's not a problem with your use, but it's not good to look at.

//

[10:51:30] [Server thread/INFO]: [dynmap] Saved 1411118 pending tile renders in world 'Biomes'
[10:51:30] [Server thread/INFO]: [dynmap] Saved 1068095 pending tile renders in world 'Taurus'
[10:51:30] [Server thread/INFO]: [dynmap] Saved 1141917 pending tile renders in world 'Wild'
[10:51:30] [Server thread/INFO]: [dynmap] Full render job saved for world 'Wild'
[10:51:31] [Server thread/INFO]: [dynmap] Saved 41 pending tile renders in world 'Wild_nether'
[10:51:36] [Dynmap Render Thread/ERROR]: [dynmap] Exception occured:
java.lang.InterruptedException: null
at java.lang.Object.wait(Native Method) ~[?:?]
at org.bukkit.craftbukkit.v1_18_R1.scheduler.CraftFuture.get(CraftFuture.java:53) ~[paper-1.18.1.jar:git-Paper-198]
at org.bukkit.craftbukkit.v1_18_R1.scheduler.CraftFuture.get(CraftFuture.java:40) ~[paper-1.18.1.jar:git-Paper-198]
at org.dynmap.bukkit.DynmapPlugin$BukkitServer.createMapChunkCache(DynmapPlugin.java:543) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$FullWorldRenderState.processTile(MapManager.java:761) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$FullWorldRenderState.run(MapManager.java:720) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$DynmapScheduledThreadPoolExecutor$1.run(MapManager.java:229) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$DynmapScheduledThreadPoolExecutor$2.run(MapManager.java:245) ~[Dynmap-3.3.2-spigot.jar:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539) ~[?:?]
at java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[?:?]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[?:?]
at java.lang.Thread.run(Thread.java:833) ~[?:?]
[10:51:36] [Dynmap Render Thread/ERROR]: [dynmap] Exception occured:
java.lang.InterruptedException: null
at java.lang.Object.wait(Native Method) ~[?:?]
at org.bukkit.craftbukkit.v1_18_R1.scheduler.CraftFuture.get(CraftFuture.java:53) ~[paper-1.18.1.jar:git-Paper-198]
at org.bukkit.craftbukkit.v1_18_R1.scheduler.CraftFuture.get(CraftFuture.java:40) ~[paper-1.18.1.jar:git-Paper-198]
at org.dynmap.bukkit.DynmapPlugin$BukkitServer.createMapChunkCache(DynmapPlugin.java:543) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$FullWorldRenderState.processTile(MapManager.java:761) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$FullWorldRenderState.run(MapManager.java:720) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$DynmapScheduledThreadPoolExecutor$1.run(MapManager.java:229) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$DynmapScheduledThreadPoolExecutor$2.run(MapManager.java:245) ~[Dynmap-3.3.2-spigot.jar:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539) ~[?:?]
at java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[?:?]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[?:?]
at java.lang.Thread.run(Thread.java:833) ~[?:?]
[10:51:36] [Dynmap Render Thread/ERROR]: [dynmap] Exception occured:
java.lang.InterruptedException: null
at java.lang.Object.wait(Native Method) ~[?:?]
at org.bukkit.craftbukkit.v1_18_R1.scheduler.CraftFuture.get(CraftFuture.java:53) ~[paper-1.18.1.jar:git-Paper-198]
at org.bukkit.craftbukkit.v1_18_R1.scheduler.CraftFuture.get(CraftFuture.java:40) ~[paper-1.18.1.jar:git-Paper-198]
at org.dynmap.bukkit.DynmapPlugin$BukkitServer.createMapChunkCache(DynmapPlugin.java:543) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$FullWorldRenderState.processTile(MapManager.java:761) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$FullWorldRenderState.run(MapManager.java:694) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$DynmapScheduledThreadPoolExecutor$1.run(MapManager.java:229) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$DynmapScheduledThreadPoolExecutor$2.run(MapManager.java:245) ~[Dynmap-3.3.2-spigot.jar:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539) ~[?:?]
at java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[?:?]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[?:?]
at java.lang.Thread.run(Thread.java:833) ~[?:?]
[10:51:36] [Dynmap Render Thread/ERROR]: [dynmap] Exception occured:
java.lang.InterruptedException: null
at java.lang.Object.wait(Native Method) ~[?:?]
at org.bukkit.craftbukkit.v1_18_R1.scheduler.CraftFuture.get(CraftFuture.java:53) ~[paper-1.18.1.jar:git-Paper-198]
at org.bukkit.craftbukkit.v1_18_R1.scheduler.CraftFuture.get(CraftFuture.java:40) ~[paper-1.18.1.jar:git-Paper-198]
at org.dynmap.bukkit.DynmapPlugin$BukkitServer.createMapChunkCache(DynmapPlugin.java:543) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$FullWorldRenderState.processTile(MapManager.java:761) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$FullWorldRenderState.access$1300(MapManager.java:262) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$FullWorldRenderState$3.call(MapManager.java:686) ~[Dynmap-3.3.2-spigot.jar:?]
at org.dynmap.MapManager$FullWorldRenderState$3.call(MapManager.java:684) ~[Dynmap-3.3.2-spigot.jar:?]
at java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[?:?]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[?:?]
at java.lang.Thread.run(Thread.java:833) ~[?:?]
[10:51:36] [Server thread/INFO]: [dynmap] Disabled

It does something similar on my Spigot server as well, that is not only for restart, just whenever it need to save data and disable itself (shutdown, reload, whatnot...).

Already fixed in SNAPSHOTs