renderItem on Polaris ResourceList renders multiple times?

Shopify Partner
25 2 24

I'm using the Polaris component ResourceList.  I set the renderItem with extensive (ie. cpu intensive) code.  The code seems to run multiple times even thought the "items" are constant and never changed.


I've created a test code sandbox you can see here.  Look at the console output:


Am I understanding this correctly? It seems that it is rendering the items 4 times.


Should it be behaving this way?