Qatar - 5% Withholding Tax

As I am still based in Dubai while servicing a company contract in Qatar, I invoice monthly from Dubai. With effect from August 1st, the client has started to withhold 5% of the invoiced amount, apparently in line with a new Qatari law. It appears that all expats working in Qatar without Qatari residency are to be taxed at 5%, from now on. Qatar introduced this before, a couple of years ago, and withdrew it when all the major international companies simply put their rates up to compensate, and by more than the 5%. It's not obvious why Qatar thinks it will be any different this time around, but time will tell. Anyone else being affected by this?