Why does TTS butcher brand names? (JPEG, Versace, niche vocab)

I'm building an e-learning course on networking and the narrator keeps mangling brand names and acronyms. It's not a small problem either — every module is full of them. JPEG comes out as "Jay-Pea-Ee-Gee" letter by letter, Versace lands with a stress on the wrong syllable, and technical words like 'gigabytes' and 'RAM' are a coin flip depending on the sentence.