OK, I checked it on Adaptive Server Enterprise/15.7/EBF 21521 SMP SP102 /P/x86_64/Enterprise Linux/ase157sp101/3445/64-bit/FBO/Sat Jul 13 02:28:53 2013
Still the same.
I'll report this to TechSupport. BTW, I've already opened a case with our Polish Partner's TechSupport but they answered that this is correct behaviour (!?!)...
Thank you!