I wrote "Nie lubi", because - and on repeated hearings - the audio, played at normal speed, does not have the final sound "ę " for the first person. However, in the slow mode, the sound is clearly there. Now I wonder: Is this something that happens regularly, in actual speech, i.e. that a final sound is swallowed/omitted?
No. Whenever it seems to you that some letter wasn't in the audio, it's for 99% one of the following:
The audio is simply bad.
You're not accustomed to the Polish sounds yet (for example many learners ask if the 'p' at the beginning of the word is silent and we have absolutely no clue what they're talking about, of course it's there).
You don't realize that a letter is a part of a digraph.
Words which really have a silent letter (or perhaps: in which it is acceptable to not pronounce a letter) could be counted on my fingers.
One other thing: if "ę" is the final sound in a word, most people pronounce it as a normal "e". But well, that would not cause you to write "lubi" but perhaps "lubie".
And here we have... of course, number one! The female audio does indeed say "lubi" :/ I disabled it for the audio exercises.