Cloning an Mbed project from GitHub into the latest version of Keil Studio Cloud (1.6.6) generates multiple invalid intellisense errors. It seems like intellisense is essentially completely broken; it reports errors stemming from an inability to find "mbed.h", and it reports errors on standard library function calls. The project is a sea of red underlines. This occurs even though the project builds fine. Confirmed on multiple accounts by several people (I am an educator so I have a large testing pool!).
This appears to be a regression; I see reports such as this one from last year that seem identical.
Screenshot:
The update to 1.6.9 appears to have resolved the issue. For the record this problem seemed independent of the mbed-os version on 1.6.6, I tried several.
I have also had a couple of reports from students who have seen this issue resolve itself, presumably with the version change, so I think it's safe to consider this closed unless it recurs.