uic produces nondeterministic output

While working on reproducible builds for openSUSE, I found that

our kopete-19.2.3 package does not build reproducibly

unless ASLR is disabled.

I traced this down to this reproducer:

for i in $(seq 1 6) ; do

  "/usr/lib64/qt5/bin/uic" "-tr" "tr2i18n" "/home/abuild/rpmbuild/BUILD/kopete-19.12.3/protocols/oscar/aim/ui/aimeditaccountui.ui" > x && md5sum x ; done|sort|uniq -c

actual output:

4 7b8cab4b8b6651929ffd825f9f9f6a6a x
2 9ca02f5f2069387fd453192c42aeb848 x

expected output:

should always produce the same output, e.g.

6 7b8cab4b8b6651929ffd825f9f9f6a6a x

diffs look thus:

+++ /home/abuild/rpmbuild/BUILD/kopete-19.12.3/build/protocols/oscar/aim/ui_aimeditaccountui.h 2035-05-03 18:25:27.547478119 +0000
@@ -533,7 +533,7 @@
{{ retranslateUi(aimEditAccountUI);}}
{{ QObject::connect(optionOverrideServer, SIGNAL(toggled(bool)), lblServer}}
, SLOT(setEnabled(bool)));
{{ QObject::connect(optionOverrideServer, SIGNAL(toggled(bool)), edtServer}}
Address, SLOT(setEnabled(bool)));
- QObject::connect(optionOverrideServer, SIGNAL(toggled(bool)), lblPort,
SLOT(setEnabled(bool)));
+ QObject::connect(optionOverrideServer, SIGNAL(toggled(bool)), lblPort1,
{{ SLOT(setEnabled(bool)));}}

uic also outputs warnings that seem related:

/home/abuild/rpmbuild/BUILD/kopete-19.12.3/protocols/oscar/aim/ui/aimeditaccountui.ui: Warning: The name 'lblPort' (QLabel) is already in use, defaulting to 'lblPort1'.