DISCLAIMER: this is just my experience "AS IS", maybe I'm missing some important details, then please let me know!
Also had this error after app update, and finally after few attempts it has disappeared. I'm not an expert in GDPR, just want to share my experience, maybe (hope) there is a better solution.
What I've tried (don't do this, it didn't removes AdMob error):
- Disable personalize ads in AdMob console
- Remove UMP lib and release an update
- Remove ad units with errors and release an update
After every of this attempts I still got error message. I know it requires time to disappear, if no new errors comes, but after few days errors count was increasing, and even newly added ad units were in report, but I added them in app version without UMP lib.
After reading some TCF strings docs, I realized that TCF strings still exist on user devices and AdMob uses them. After logging all default shared prefs I've got something like:

So, next I released an app update, with TCF strings cleanup on app launch:
private fun clearTcfData(context: Context) {
val prefs = PreferenceManager.getDefaultSharedPreferences(context)
val tcfKeys = prefs.all.keys.toList().filter { it.startsWith("IABTCF", true) }
if (tcfKeys.isNotEmpty()) {
prefs.edit {
tcfKeys.forEach { remove(it) }
}
}
}
Then soon I saw less errors in TCF error report, and after about 10 days TCF error banner has disappeared. Also I enabled personalized ads again, cause this doesn't cause a problem. To sum up, solution that works for me is:
- Replace UMP lib with old EU consent lib
- Clear remaining TCF strings on app launch
- Release and wait