Memory allocated by QString::toUtf8() is freed too early

Before I start. The issue I describe happens in ALL versions of Qt. I tested it on 4.8.4, 5.15.16 and 6.6.1 .

When I need a char-pointer to the UTF-8 representation of a QString, I do it like this:
const char * foo = myQString.toUtf8().constData();

But it appears that the memory allocated by toUtf8() is freed too early and thus available for reuse! Which happens on the next call to toUtf8(), for example.

const char * foo = myQString.toUtf8().constData();
const char * bar = anotherQString.toUtf8().constData();

I have seen that anotherQString.toUtf8() uses the exact same memory, and hence, foo does not point to the expected UTF-8 representation of myQString.

So, what is the 'lifetime' of the Memory allocated by toUtf8()?
Until the next call to toUtf8()? How can I be sure the memory is not touched by another process or thread?

As a 'solution' I store the result of toUtf8() in a local QByteArray, but it feels uncomfortable knowing that many libraries and Qt itself use myQString.toUtf8().constData(); frequently too!

I have attached an example project showing what happens.

Example of program output:
Qt version: 6.6.1
OS: Linux

show bug
1 foo=foo (0x0x5e8acd663910)
2 foo=bar (0x0x5e8acd663910)
3 bar=bar (0x0x5e8acd663910)
foo memory is reused/overwitten by bar UTF-8 data!

show postponed fix
1 foo=foo (0x0x5e8acd663910)
2 foo=foo (0x0x5e8acd663910)
3 bar=bar (0x0x5e8acd663960)
foo is OK
4 foo=foo (0x0x5e8acd663910)
5 bar=qux (0x0x5e8acd663960)
6 qux=qux (0x0x5e8acd663960)
bar memory is reused/overwitten by qux UTF-8 data!

show permanent fix
1 foo=foo (0x0x5e8acd663910)
2 foo=foo (0x0x5e8acd663910)
3 bar=bar (0x0x5e8acd663960)
foo is OK
4 foo=foo (0x0x5e8acd663910)
5 bar=bar (0x0x5e8acd663960)
6 qux=qux (0x0x5e8acd663990)
bar is OK