Possible charset problem

I am getting strange issue. When i add string text to some uiComponent which contains special UTF-8 characters like šťčľťťžíľáš element is created correctly and displayed correctly on screen. But only for while. After some time i get something like this:

Objednávka dopravy č.: 21/243636/4712

exept something like this:

Objednávka dopravy č.: 21/243636/4712

i tried passing string value with UTF-8 charset but no change.

Hi,
Can you create a small demo project and describe a scenario reproducing this problem?
Which CUBA platform version and which database do you use?