I was approached to fill a position in an organisation, and during salary negotiations, I was told that they wouldn't budge on the salary because employees were expected to get a pay raise in April the following, and if you were to add up the bonus, the annual package would be sufficient.

Given this, I took up the job, but when I started, HR told me that I wouldn't actually be eligible for the salary raise NOR the bonus till April 2021. Which would meant that I took a severe pay cut taking up this job.

And the organisation + job isn't turning out like what was mentioned in the interviews/job description at all. People are stubborn and are not willing to change what I think are serious breaches in governance (e.g. finance and procurement lumped together).

It's only been 2 weeks, but I feel that because I was misled into the job, it would only be right for me to leave. To what extent should I tell my interviewers about my reason for leaving?