Story

Hello!

I decided to test Regional Compliances and add My System Region (Russia) using ISO_3166-1_alpha-3 Code in Region Param with same Messages just to test this Feature and may be use it for self-caution about Minecraft Addiction.
I found that Timer can be cancelled after using Resource Pack with invalid Edit of the regional_compliancies.json File and even after troubleshooting the Resource Pack, the Resource Pack can't be applied because of "Already cancelled Timer"(Caught Error is listed below).

Error Messages:

Caught error loading resourcepacks, removing all selected resourcepacks
java.util.concurrent.CompletionException: java.lang.IllegalStateException: Timer already cancelled.
	at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:315)
	at java.base/java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:320)
	at java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:722)
	at java.base/java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:482)
	at aua.a(SourceFile:69)
	at bot.d(SourceFile:162)
	at box.d(SourceFile:23)
	at bot.A(SourceFile:136)
	at bot.bA(SourceFile:121)
	at ffn.c(SourceFile:1239)
	at ffn.f(SourceFile:880)
	at net.minecraft.client.main.Main.main(SourceFile:265)
Caused by: java.lang.IllegalStateException: Timer already cancelled.
	at java.base/java.util.Timer.sched(Timer.java:409)
	at java.base/java.util.Timer.scheduleAtFixedRate(Timer.java:340)
	at fft.a(SourceFile:95)
	at fft.a(SourceFile:30)
	at atz.a(SourceFile:13)
	at java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:718)
	... 9 more

How it was produced

The invalid editing was changing the Message or Title parametres to

[{"text":"<text>"}]

and troubleshooting in this case is returning to Standard "<text>".

Expected Behavior:

Resource Pack should be appliable after Troubleshooting.

Observed Behavior:

Resource Pack can't be applied.

How to reproduce:

0. Apply addict_timer.zip,
1. Wait for first Appearing of Time Toast,
2. Unapply addict_timer.zip and apply addict_timer_gone_wrong.zip,
3. Wait for 1 minute (or better to wait 1-2 minute(s)),
4. Unapply addict_timer_gone_wrong.zip and reapply addict_timer.zip,
5. Resource Pack can't be applied because of some Error (all Information is above and in the pinned Comment(s))

Regional Compliances' Timer Error after Resource Pack Troubleshooting.