Clazy function-args-by-ref: is this a false-positive or intentional?

Running Clazy with function-args-by-ref on Elisa gives a warning here src/modeldataloader.cpp · dfb15e3ae3cd023a9a6346b1dd814a1144367313 · Multimedia / Elisa · GitLab. The issue is with the first argument, trackDataType, which effectively takes a QList<QMap> by value. Taking by value is intentional here as we modify the contents of the list, so I am inclined to think that Clazy is reporting a false-positive. However, this function is marked as a Q_SLOT so perhaps there is some under-the-hood reason why this argument should be taken as a const-ref?