Consider the word 'future.' Cambridge Dictionary shows the transcriptions /ˈfjuːtʃəʳ/ and /ˈfjuːtʃɚ/. Are they different?
One is the Standard British English pronunciation, and the other is the General American English pronunciation.
In the British pronunciation, you don't pronounce the /r/ after /ə/ unless the next word starts with a vowel. (The superscript /r/ is saying add an /r/ after it if the next word starts with a vowel. Compare the words store /stɔːʳ/ and star /stɑːʳ/.)
In American pronunciation, you combine the vowel /ə/ and the /r/ into a single r-colored vowel represented by /ɚ/.
They're the same phoneme; it's just pronounced differently in British and American English.