Hey there @AllieNguyen - this is a known bug in this release (related) - this should be fixed in the upcoming 2018.8 release of QIIME 2. In the meantime, you can always plot the values in the CSVs in the tool of your choice. Thanks! 
Hey there @AllieNguyen - this is a known bug in this release (related) - this should be fixed in the upcoming 2018.8 release of QIIME 2. In the meantime, you can always plot the values in the CSVs in the tool of your choice. Thanks!