clang failing due to header not found, filesystem race condition

Created by: sheldonneuberger-sc

I'm seeing an intermittent issue where occasionally clang fails due to a header file not being found. However, I login to the machine and can see the header file there in buck-out. It seems like some kind of race condition where buck sets up the symlink for the header but that operation doesn't finish before buck runs clang which depends on that header.

Has anyone seen something like this? Building on a fairly standard macpro setup with APFS filesystem with disk mount properties (apfs, local, journaled).