It was in Poland. It was mocked because it's very unusual and comes across as unnecessary, pretentious and uneducated. Everyone knew
Karolina and
Charlotte but for most of us (all?) this was the first time we encountered Szarlota. I suppose it's how kre8yv spellings are perceived by many English speakers. Most people would say to just use
Charlotte if you're so hard pressed or even better the traditional
Karolina.
Interestingly, this is just how the name comes off nowadays. But in reality, it seems that, while the name was never widely used, whatever little actual use it did get must have been pretty long ago. Since 2010 no Szarlotas were born (or almost none, at most one a year). And the total number of Szarlotas in Poland more than doubles when deceased people are included in the data set (both are tiny numbers: 314 vs 750 but the decline is very steep).
https://www.behindthename.com/pnl/109883