The sound is perfectly correct. It is [tɪ], not [ti:] (that would have been written TÝ if it existed). Check https://en.wikipedia.org/wiki/Czech_phonology#Vowels or recordings at forvo.com.
Wikipedia not really helpful. Shows "/ɪ/ is spelled i and y" under short vowels. OK, that's not showing how it is pronounced. Further down, shows this "/ɪ/" sound example "litovat" and "vykonat". Seems incorrect from way I was taught--"moc lituju" is not pronounced "mots lehtuju" but "mots leetuju". In German, there are many dialects, Hoch Deutsch vs. Swabian, etc. Is this a distinction between dialects? Let me have a 'listen' at forvo.com--ok, that sounds to me like "tee" with a short hold on the "ee" and not "teh". I understand the distinction between long and short vowels; I don't think that's the issue. Perhaps the issue is my computer's speaker! Just thought of that. Not really high fidelity speakers on my computer.