The manual construction of the horno oven for roasting agave for mezcal is a lovely piece of traditional labour, long may it continue. The workers could do with some respiratory protection, though, looks smokey.
When a common word from another language is borrowed into English, it tends to take on a more specific meaning. Most native English speakers wouldn't use "salsa" to describe any other sauce. Horno oven sounds perfectly reasonable in English to specifically describe an earth oven in that style, not the common household appliance.
EDIT: Probably the reason this happens is that most English speakers wouldn't be familiar with the foreign word, so the speaker uses it as a modifier to the standard English word. The listener doesn't need to know anything specific about the foreign word in that case and can just assume it's a type of the common item.
I think the acronym thing is related but a separate phenomenon. My guess would be that speakers intuitively think the acronym isn't easily understandable so they add an extra word to clarify it, intentionally or unintentionally duplicating one of the actual words in the acronym.
"pont bridge" sounds like the exact phenomenon though. Does it have a more specific meaning that "bridge"?
My argument is that it's not a mistranslation. In Spanish, "horno" means any kind of oven. In English, it means specifically an earth oven because when English speakers started using the word, they always used it to mean that kind of oven.
A sibling comment mentioned chai tea. It's the same phenomenon. Chai means any tea in its original language, but in English it means a specific variety and preparation of tea.
English is a bastardized language and has a lot of words borrowed from other languages. But once they're borrowed, they're English words and have their own meaning separate from their original loanword.
If it was shipped over land across the Silk Road, its name stems from 'cha' (茶). However, if it was shipped from the coast, the dialect spoken there pronounced 茶 as 'te'.
https://youtu.be/IEEsu6PFGF0