used qt 5.10.0, msvc2015 32bit，my qt project .pro file is:
#-------------------------------------------------

Project created by QtCreator 2022-07-26T16:57:19

#-------------------------------------------------
QT += core gui concurrent

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++11

DESTDIR = $$PWD/./bin
TARGET = log4qt_test

DEFINES += QT_DEPRECATED_WARNINGS

DEFINES +=LOG4QT_STATIC

LOG4QTSRCPATH = $$PWD/log4qt

INCLUDEPATH += -L $$LOG4QTSRCPATH
$$LOG4QTSRCPATH/helpers
$$LOG4QTSRCPATH/spi
$$LOG4QTSRCPATH/varia

DEPENDPATH += $$LOG4QTSRCPATH
$$LOG4QTSRCPATH/helpers
$$LOG4QTSRCPATH/spi
$$LOG4QTSRCPATH/varia

include($$PWD/log4qt/log4qt.pri)
include($$PWD/log4qt/build.pri)
include($$PWD/log4qt/g++.pri)

include(logger/logger.pri)

SOURCES +=
main.cpp
mainwindow.cpp

HEADERS +=
mainwindow.h

FORMS +=
mainwindow.ui

qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

LIBS += -L$$PWD/./bin

from log4qt.

i used heob tools in Qtcrator4.15, 64bit, the result is the same,both 32 bit and 64bit have the same probloms:

The more debug log info taked ,the more memory will be occupied

from log4qt.

the test project can be downloaded from here:
https://blog.csdn.net/yyz_1987/article/details/126017464

from log4qt.