diff --git a/src/corelib/text/qcollator_icu.cpp b/src/corelib/text/qcollator_icu.cpp
index afd58b5d5e..84f9c51537 100644
--- a/src/corelib/text/qcollator_icu.cpp
+++ b/src/corelib/text/qcollator_icu.cpp
@@ -81,6 +81,7 @@ int QCollator::compare(QStringView s1, QStringView s2) const
     d->ensureInitialized();
 
     if (d->collator) {
+        // truncating sizes (QTBUG-105038)
         return ucol_strcoll(d->collator,
                             reinterpret_cast<const UChar *>(s1.data()), s1.size(),
                             reinterpret_cast<const UChar *>(s2.data()), s2.size());
@@ -98,6 +99,7 @@ QCollatorSortKey QCollator::sortKey(const QString &string) const
 
     if (d->collator) {
         QByteArray result(16 + string.size() + (string.size() >> 2), Qt::Uninitialized);
+        // truncating sizes (QTBUG-105038)
         int size = ucol_getSortKey(d->collator, (const UChar *)string.constData(),
                                    string.size(), (uint8_t *)result.data(), result.size());
         if (size > result.size()) {
diff --git a/src/corelib/text/qcollator_win.cpp b/src/corelib/text/qcollator_win.cpp
index 405337924f..b588f5ff46 100644
--- a/src/corelib/text/qcollator_win.cpp
+++ b/src/corelib/text/qcollator_win.cpp
@@ -96,6 +96,7 @@ QCollatorSortKey QCollator::sortKey(const QString &string) const
     if (d->isC())
         return QCollatorSortKey(new QCollatorSortKeyPrivate(string));
 
+    // truncating sizes (QTBUG-105038)
     int size = LCMapStringW(d->localeID, LCMAP_SORTKEY | d->collator,
                            reinterpret_cast<const wchar_t*>(string.constData()), string.size(),
                            0, 0);