If you are a single person then part of your income should be taxed at 41%.
Have you informed Revenue that you have 2 jobs, or are all your credits and cut-off points with job A and none allocated to job B.
If employers B has no tax credit Cert for you then he must tax you at the Emergency rate (41%).
Depending on how much you earn in either job you can distribute tax credits and cut-off points in the way that suits you best. Talk to Revenue and they will advise you on the best allocation. The phone number of your district is on the tax credit Cert