Comment # 3 on bug 1212698 from Bernhard Wiedemann

The difference is with osc build -j1 and -j2 : so 1-core-VM vs 2-core-VM which
influences scheduling of forked processes / threads.
You might be able to replicate it with taskset 1 vs 3.

Here is the full reproducer script:
#!/bin/sh
osc co openSUSE:Factory/photoqt && cd $_
for N in 1 2 ; do
    osc build --vm-type=kvm --noservice -j $N --keep-pkg=RPMS.$N
    unrpm RPMS.$N/photoqt-*.x86_64.rpm
    hexdump -C usr/bin/photoqt > $N.strings
done
diff -u {1,2}.strings


and I noticed more diff:
 00548030  08 6a 54 00 00 00 00 00  00 00 00 00 00 00 00 00  |.jT.............|
 00548040  70 68 6f 74 6f 71 74 2e  64 65 62 75 67 00 00 00  |photoqt.debug...|
-00548050  76 67 8b 32 00 2e 73 68  73 74 72 74 61 62 00 2e  |vg.2..shstrtab..|
+00548050  cf 99 c4 a7 00 2e 73 68  73 74 72 74 61 62 00 2e  |......shstrtab..|
 00548060  69 6e 74 65 72 70 00 2e  6e 6f 74 65 2e 67 6e 75  |interp..note.gnu|
 00548070  2e 70 72 6f 70 65 72 74  79 00 2e 6e 6f 74 65 2e  |.property..note.|
 00548080  67 6e 75 2e 62 75 69 6c  64 2d 69 64 00 2e 6e 6f  |gnu.build-id..no|