No, that's correct. German (contrary to English) has phonemic contrast between [ə] and [ɐ]: eine = /aɪnə/
einer = /aɪnɐ/
The two reduced vowels /ə/ and /ɐ/ are also called e-Schwa and a-Schwa.
The symbol stands for the near open central unrounded oral vowel. It overlays with the German short "a". The only difference is that the short "a" /a/ is a full vowel and /ɐ/ is, like /ə/, a reduced vowel. If it weren't for this full-reduced vowel difference, it would probably be better to transcribe the short "a" /ɐ/ as well.
You can compare this sound with English "Doctor" in the early Doctor Who series.
In case of "immer" there are a lot of variants.
I speak it usually a little bit sliding from
ə to ɐ: einer = /aɪnəɐ/ (I'm not sure if this is correct IPA)
But there is no difference in meaning.
The important contrast is between ə and ɐ eine = /aɪnə/
einer = /aɪnɐ/ (in my case female /aɪnə/ vs. male /aɪnəɐ/ sliding from e-schwa to a-schwa - may be this is regional)
as Bernd mentioned.