"A professional job"
Translation:Ett professionellt arbete
For indefinite singular, you have common gender: "professionell" and neuter gender: "professionellt". We see the indefinite neuter article "Ett" in the sentence, so we are sure which to use. "Professionella" would be the plural form of the word, so would be used with "arbetena"; it's also the definite form (except when masculine gender) so it would be used with "arbetet", but not with "arbete".
It sounds like in this one, the TTS voice uses a "sh" sound for the "ss", whereas all other instances of "professionell" (which may have all been different declensions) I've come across used the "sj" sound. Is this a quirk of this particular declension, are both pronunciations valid or is something up with the TTS voice in this case?