[regression 5.12 -> 5.13] lrelease problem with TRANSLATIONS variable in subdirs project

Having a project of subdirs type in which a translation variable is defined:

TEMPLATE = subdirs
SUBDIRS += SubProject1 \
           SubProject2
TRANSLATIONS += translations/fa-IR.ts

lupdate works normal and creates a .ts file in the directory. But running lrelease does not create any .qm file.

This is the output messages of lrelease:

Starting external tool "C:\Qt\Qt5.13.0\5.13.0\msvc2017_64\bin\lrelease.exe" C:/projects/Test/Test.pro
Info: creating stash file C:\projects\Test\.qmake.stash
 
"C:\Qt\Qt5.13.0\5.13.0\msvc2017_64\bin\lrelease.exe" finished

Even if I move TRANSLATIONS += translations/fa-IR.ts to SubProject1, there is no difference and the problem remains.

Only if i add TRANSLATIONS += translations/fa-IR.ts to a sub project and open the .pro file  of the subproject separately in Qt Creator, lrelease works and creates the .qm file.

I had not this issue in Qt 5.12.