The problem is that one (ambiguous) term in English can cover more meanings or scenarios while in other language it may be required different words based on situation, for instance "lap" in swimming pool or stadium, heck even very basic "subscribe" can differ whether you are subscribing paid service or some free content in some languages, while in English you can easily use same word for both scenarios.

One would think TM and glossaries are the very basic requirements when requesting translation to update already existing translation, but I agree some companies don't provide these, which can cause inconsistencies when changing translator/company.