multiple armorstand for hologram + start error

[erposse90]

hi, I put this beautiful plugin in my magma server and I encountered two errors: the first is that it creates multiple armorstands, causing absurd lag, when reloading the world or reloading the chunk (?) the second is this error in console, which I do not know if it is related to the first

18.01 09:57:13 [Server] Craft Scheduler Thread - 6/WARN [de.epiceric.shopchest.ShopChest]: [ShopChest] Plugin ShopChest v1.12.3 generated an exception while executing task 51
18.01 09:57:13 [Server] INFO java.lang.NullPointerException: null
18.01 09:57:13 [Server] INFO at de.epiceric.shopchest.utils.UpdateChecker.check(UpdateChecker.java:43) ~[?:?]
18.01 09:57:13 [Server] INFO at de.epiceric.shopchest.ShopChest$4.run(ShopChest.java:321) ~[?:?]
18.01 09:57:13 [Server] INFO at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftTask.run(CraftTask.java:78) ~[CraftTask.class:46f4149]
18.01 09:57:13 [Server] INFO at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:52) [CraftAsyncTask.class:46f4149]
18.01 09:57:13 [Server] INFO at com.destroystokyo.paper.ServerSchedulerReportingWrapper.run(ServerSchedulerReportingWrapper.java:22) [ServerSchedulerReportingWrapper.class:46f4149]
18.01 09:57:13 [Server] INFO at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_211]
18.01 09:57:13 [Server] INFO at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_211]
18.01 09:57:13 [Server] INFO at java.lang.Thread.run(Thread.java:748) [?:1.8.0_211]