Bug Report

Type /ver NametagEdit and post the output.
4.4.8 (I tried it with the latest stable version too)

What version of Bukkit/Spigot/PaperSpigot are you using? Type /ver
PaperSpigot
git-Paper-282 (MC 1.15.2)

What plugins are you using? Type /plugins
AdvancedBan*, Aliases*, AntiVPN, AuthMe, BedWars, BuildBattle, ChatControl, Citizens, CommandExecutor*, CommandPanels, CoreProtect, CrazyCrates, CustomCommands, DeluxeHub, DiscordSRV, Essentials, EssentialsSpawn, FastAsyncWorldEdit, Gatekeeper*, GCore, GriefPrevention, HolographicDisplays, HungerGames, IridiumSkyblock, KP-PVP, LaggRemover, LitePlaytimeRewards, LuckPerms, Multiverse-Core, Multiverse-Inventories, MurderMystery, NametagEdit*, OldCombatMechanics, PlaceholderAPI, PlayerTracker*, RandomSpawn, Scoreboard-revision*, ServerLog, SkinsRestorer, Skywars, StaffPlus, SuperVanish, Vault, VoidGenerator, WitherAC, WorldEdit, WorldGuard, WorldGuardExtraFlags, WorldSpawns

Please explain your issue. How do you trigger it?
When I activated RefreshInterval on the config, the username started to blink from the edited version to the unedited version of the name at the pace of the refresh.

Are there any errors in the console? Please use: https://pastebin.com
Nope.
Actually, yes, on debug mode. https://pastebin.com/YvmZVbBi