I wouldn't work at a church that felt it had the right to tax my paycheck. Show me where it's biblical. I don't think it's that common, but I do know of a church that takes people out of ministry for not tithing (happened to our son, when he didn't even have a job - but nobody wanted to hear that). There may be more than one, but I don't know. Also know of a church that had a young man who interned for a whole year for no pay...young man was presented with a bill for his tithe for the year, based on what they would have paid him. He had to work another 2-3 weeks for free before he could go on to the ministry God was calling him to. Where is that in the Bible?
I don't know how common it actually is, but if the employee of the church accepts the job and that's the way they do it, well, the employee has no recourse but to put up with it. IMO, it's making tithe a tax...income tax is unconstitutional, and IMO, forced tithe is unbiblical.