This is likely due to variations in spelling and capitalization for the given tag.
In the below example, CloudHealth recognized the tag 'user:environment' which is the first line shown. Then an additional variations of the tag started to be received and both 'user:environment' and 'user:Environment' were recognized. On top of that, there is another misspelled tag that is being identified as 'user:environment_user:e1nviromment'.
The final result is 3 tag versions that you see below:
It's important to be consistent with your tagging to avoid situations where there are multiple different variations of a given tag as it can lead to confusion and potentially data being left out of reporting views if all versions aren't accounted for.