It might be a recording error, or it might not be -- there's been some interesting research around the phenomenon of humans sometimes totally mishearing one consonant sound as another if not given sufficient visual and / or contextual clues (even when the sound is perfectly-correctly produced). So, it's possible that fewer people would have heard the [l] as a [d] if they had been able to see someone saying the word (as long as the person's [l] mouth position didn't look too much like that of another consonant!). I think it also helps to hear the [l] when you know 'diquide' isn't a word (... at least, I'm pretty certain it's not ...).
I'm not sure I would've guessed [l] and [d] sounds would be so easily-muddled, but who knows ...?
I'm pretty sure liaisons only happen when you have a consonant preceding a vowel sound. For example, in the phrase "je suis aller", you would pronounce the 's' at the end of "suis" because it's followed by a vowel sound, even though the 's' is usually silent. Here however, you have a consonant sound leading into another consonant sound, so a liaison wouldn't occur.
"Liquide" is used for masculine and feminine nouns. Just because it ends in an "e," it doesn't mean that the noun has to be feminine. In French, "liquid," is not a word. Most natives would think you mean "liquide." There are some adjectives that you will have to memorize the spelling for in French.
ChantalRouette's point is well made.
With a vocabulary of a hundred words or so, there are only so many useful sentences that can be constructed.
They could have used a sentence like super cooled nitrogen is liquid but they would have to introduce a bunch of new words into the vocab just to get across the point that liquide is the same masculine or feminine.
When people say "drink wine" it's in concrete contexts like from a glass or with friends. When people say "drink the wine" it's in abstract contexts like in the potential future or generalities like rather than the water. I think this is because it is a non-count/uncountable noun. For countable nouns I find the opposite is often the case in English. Well, you asked . . .
Many people are having a problem with the sound. However, I think the problem is the sentence. Of course the wine would be liquid. Would you freeze wine? Sometime DL is too focussed on the individual words and not whether the sentence has any real or relevant meaning. For a non-English speaker sometimes DL sentences must be quite puzzling. I have news for you - they are puzzling to me too!