Memory leak in QtCreator 4.3.0

After using QtCreator normally for an hour or so, memory usage was over 7 GB (by "normal use" I mean a combination of editing code, compiling and running). Parsing was C++ files was taking a very long time to complete & whenever I pressed Ctrl+B to start a build it would take a few seconds before any output appears in the compile log. Closing files, clearing output panes, etc. didn't bring the memory use down or affect any of the other symptoms.

I only have one project open and it's a fairly small one: 67 headers, 63 cpp files.

I upgraded yesterday from QtCreator 4.2.1 and imported my settings. Since upgrading I've been using the "Flat Dark" theme. I have the Clang Code Model and Clang Static Analyser disabled.

Is there any additional info I can provide to help diagnose this?