The second sound is marginally different from the first, but both sounds fall well within the range of /ə/Check the word "Cinema" at MW or OALD
Both of them give this Phonetic for it: \ˈsi-nə-mə\ . From what I hear I am certain that "ə" shouldn't be used twice. One of these "ə"s must be replaced with anther phonetic letter because the audio says differently.
Am I the only person that hears 2 different sounds here?
Standard BrE vowels and diphthongs are represented by twelve phonemic and three or four non-phonemic single symbols for vowels, and eight or nine double symbols for diphthongs. AmE requires fewer symbols.
There is an almost infinite number of slight variations in each sound, most of which cannot be detected by the untrained ear. To take one simple example the /i:/ sound heard in bead is longer than that heard in beat in the speech of most speakers, but my beat may be longer than your bead.
A trained phonetician making a narrow transcription of the two schwa sounds in cinema might use two different symbols, or at least add subscript or superscript symbols. For most students, learners and users of dictionaries, one symbol per phoneme is sufficient.
Student or Learner