I found the unresolved Unicode <U+2713> (and also other unresolved Unicode) in my check protocol.
It should show a checkmark!
I have really a simple package with three data files only. I press the Check-button on the build-Pane and get log with a lot of unresolved Unicode.
I worked on win10 (1903 Build 18362.720): en_US windows display language, German-keyboard.
All messages in RStudio are in English. Only the Unicodes are not resolved.