QmakeEvaluator: Crash after closing and re-opening project

I doubt it's reproducible, but here's what I did:

• open QC with an existing session (which basically contains one project (QC but with another build directory))
• had code model issues... [don't know if it matters, but got no highlighting, auto completion or else, lots of restarting clangbackend on cmdline and General Messages]
• closed Project with File -> Close Project "qt-creator"
• switch to Welcome screen
• click the top most project to re-open the closed one