I downloaded and installed
tor-browser-linux64-4.0.7_en-US.tar.xz. It starts up ok. The browser says it has version 4.0.6, not 4.0.7. Update prompt window pops up after a few minutes.
Something is built wrong with this release.
This is a bug in TBB. The developers put out a security update of Tor which TBB developers built into Tor. This issue is discussed in bug entry #15637. This issue is now fixed. If you download version 4.0.8 or later it should not happen.