Issue Description: If multiple isometric views are set for one world, such as a spawn area or hub, they override each other upon trying to render each one. If all of them are attempted to be rendered at once, only the last one ends up being visible across all of them because it was the last to be rendered. In my case, I want to have multiple map type buttons for my spawn so players can view it from different angles. But, only the vertical, above map type and whichever isometric map type I last rendered end up being viewable. Interestingly though, player positions are updated correctly when switching between map types, which can be seen in the screenshots below.

• Dynmap Version: core=3.1-beta7-449, plugin=3.1-beta7-449

• Server Version: git-Paper-"8b47131da" (MC: 1.16.5)

• Pastebin of Configuration.txt: https://pastebin.com/18bMzqRb

• Server Host (if applicable): PebbleHost

• Pastebin of crashlogs or other relevant logs: None

• Other Relevant Data/Screenshots:
  
  
  
  

• Steps to Replicate: Below I have included the relevent world in the worlds.txt file. If one is to replicate it, all information should be given. To replicate, render all isometric views or each one at a time and watch as each map type is rendered then replaced/overrided by the next render.

[Y] I have looked at all other issues and this is not a duplicate (One is seemingly close to this issue, but not quite the same)
[Y] I have been able to replicate this

(I also made custom perspectives with the same values as the regular ones, since that was recommended in a similar issue here. Since I'm making this bug report, it obviously didn't do anything.)
This is what I have set in the worlds.txt file:

• name: spawn
  title: "Spawn"
  enabled: true
  sendposition: true
  sendhealth: false
  extrazoomout: 1
  visibilitylimits:
  • x0: -220
    z0: -220
    x1: 220
    z1: 220
    hiddenlimits: [
    ]
    hidestyle: air
    center:
    x: 0
    y: 64
    z: 0
    maps:
  • class: org.dynmap.hdmap.HDMap
    name: spawn0
    title: "Topographic"
    prefix: flat
    icon: images/block_world_biome.png
    perspective: iso_S_90_vlowres
    shader: stdtexture
    lighting: shadows
    image-format: default
    mapzoomin: 3
    mapzoomout: 0
    boostzoom: 0
    append_to_world: ''
  • class: org.dynmap.hdmap.HDMap
    name: spawn1
    title: "Southwest"
    prefix: st
    icon: images/block_skylands.png
    perspective: iso_SW_30_hires1
    shader: stdtexture
    lighting: shadows
    mapzoomin: 2
    mapzoomout: 3
  • class: org.dynmap.hdmap.HDMap
    name: spawn2
    title: "Southeast"
    prefix: st
    icon: images/block_world_cave.png
    perspective: iso_SE_30_hires2
    shader: stdtexture
    lighting: shadows
    mapzoomin: 2
    mapzoomout: 3
  • class: org.dynmap.hdmap.HDMap
    name: spawn3
    title: "East"
    prefix: st
    icon: images/block_world_surface.png
    perspective: iso_E_30_hires3
    shader: stdtexture
    lighting: shadows
    mapzoomin: 2
    mapzoomout: 3
  • class: org.dynmap.hdmap.HDMap
    name: spawn4
    title: "Northeast"
    prefix: st
    icon: images/block_other.png
    perspective: iso_NE_30_hires4
    shader: stdtexture
    lighting: shadows
    mapzoomin: 2
    mapzoomout: 3

You used the same prefix for all the maps, that is why they are the same

Ohhh ok, thank you. Would be nice if there was a note regarding the significance of that in the wiki or something lol