For tags with >= 10,000 questions, the tag counts are misrepresented on my StackExchange Android app. Specifically, they are reduced by a factor of 10.
Here is a screenshot of the highest tag counts on Stackoverflow (website)
And here are the same tags on the Android app:
A related phenomenon: the tags seem to be sorted correctly, it is just that the displayed numbers are wrong; see the following screenshot where numbers "drop" from 1k to 9,950.
This is on a Nexus 5 running Android 5.1.1 and Stack Exchange Android App version 1.0.73