Is this a plugin issue?

[Kang4421]

I made a tab list using your plugin called AdvancedTabOverlay.
However, the names of npcs appear in the tab list and blink.
Just in case, I attach my tab list, plugin, bukkit version, and plugin version.

Server version: git-Paper-1618 (MC: 1.12.2)
plugin version: AdvancedTabOverlay ( 1.2.3 )
my plugins : https://snipboard.io/4knPCT.jpg
my tab list : https://paste.md-5.net/lihekirixe.http

[CodeCrafter47]

It is normal for NPCs to appear on the tab list for a brief moment when you walk near them. Should NPCs stay on the tab list permanently, then that is likely an issue with the NPC plugin.

[Kang4421]

Then, can't we make NPC invisible?

[CodeCrafter47]

They need to appear on the tab list for a brief period of otherwise they would be completely invisible (not just on the tab list).

[Andre601]

Plugins like Citizens do remove the NPC shortly after they appear on tab.
It's an "issue" that is unfixable.
As CodeCrafter mentioned should you report this to the NPC plugin dev if the NPC doesn't disappear.