Change employer

Hello all
I am a work permit B holder and now is changing employer, just wondering currently how long it takes, I started to apply the new permit since August, up to now no news.I found some cases in this forum that some people's permit B have been rejected, anybody knows the reason? I am really worried about mine as I changed my job industry completely.
If anybody can share your experience, would be nice.

A similar thread was opened in JUne with same subject :)https://www.expat.com/forum/viewtopic.php?id=790060

Rejections are rare, but for the ones rejected common reasons are salary not meeting the requirements.