CLion syntax highlighting generates spurious errors

Since upgrading to the latest release this morning which uses Clangd for completion, I'm getting lots of spurious errors on Mac OSX for example:

It can't resolve std::endl correctly:

It's having problems with std::vector<uint32_t>:

This is clearly not good, everything worked reasonably well before the update (not perfectly but was much more usable than this!).

CLion 2019.3
Build #CL-193.5233.103, built on November 27, 2019
Runtime version: 11.0.4+10-b520.11 x86_64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
macOS 10.15.1
GC: ParNew, ConcurrentMarkSweep
Memory: 1987M
Cores: 12
Registry: run.processes.with.pty=TRUE
Non-Bundled Plugins: com.intellij.properties