Crashlytics custom key not being set as expected

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[REQUIRED] Step 2: Describe your environment

Android Studio version: Ladybug
Firebase Component: Crashlytics
Component version: 33.3.0

[REQUIRED] Step 3: Describe the problem

I'm trying to set a custom key temporarily per recorded log/exception and I'd expect the tag I have set prior to calling log or recordException to be present in the dashboard as I "send" (I know they get queued) the event immediately after setting the tag, but before unsetting it. However the custom key that does actually get set is the empty string one "" (see screenshot).

The docs suggest this should not be the case:

Sets a custom key and value that are associated with subsequent fatal, non-fatal, and ANR reports. Multiple calls to this method with the same key update the value for that key. The value of any key at the time of a fatal, non-fatal, or ANR event is associated with that event.

Is there a way to get this to work or is it inherently asynchronous somewhere?

Steps to reproduce:

Run the code below.

Relevant Code:

val crashlytics = Firebase.crashlytics
val tagKey = "tag"
try {
    val logTag = "Some temporary tag"
    crashlytics.setCustomKey(tagKey, logTag)
    crashlytics.log(message)
    crashlytics.recordException(throwable)
} finally {
    crashlytics.setCustomKey(tagKey, "")
}

firebase / firebase-android-sdk