Changes to a single sub-project .pro file triggers reloading of whole subdirs project

I have a qmake SUBDIRS project in the form

TEMPLATE = subdirs
SUBDIRS = \
    folder1/code/project1.pro \
    folder2/code/project2.pro \
# etc., about 120 projects in total

Each of the single references projects is rather small, in the range of 10 to 100 files.

When I add a class or a source file to a specific .pro file (through the wizard or manually), Creator re-loads the whole SUBDIRS project. This takes about 30 seconds in my case. During this time, I cannot use the wizard to add more files, because the context menu items are greyed until the project has been fully reloaded. Adding multiple files through the wizards is thereby a very cumbersome process.

Expected behavior: Creator only reloads the changed projects.