I get the subject diag printed in the console when starting QT Creator. The "..." is usually 173 but I doubt it's a constant.

It looks like somewhere in the initialization the registration of that tracker is done twice, which may or may not be innocuous.

I searched the web with the bug text and it shows up in other problem reports but doesn't seem related to their problem (it was just on the console when they copied all the text including diags that did relate to their problems).

Seeing the version selector box here says that 3.5.1 is a really old version of QT Creator. But it's the version that Ubuntu installs with `sudo apt install qtcreator` so there might be some value to maintaining it, or pushing Ubuntu to catch up.