Not a chance of that happening. Employment-based green cards were created for the purpose of filling the types of jobs that are in high demand/skills shortage in the US. Allowing changing to "any job" would defeat that purpose.
Anyway, remember that it refers to the same or similar occupational classification, not necessarily a job that is exactly like the one you had before, so there is still a good amount of flexibility. Also, you can use your EAD to work at any job, but you just have to make sure that you will work for a same or similar type of job when you get the green card, and that if they send an RFE before you get the green card then you can prove that you have an offer for a same or similar type of job.
