Same thing happened with Naruto. Every year, outside of the mangaka's personal breaks, the magazine has 4 magazine breaks, which are referred to as double issues, where every series in the magazine has a break. This one is I believe 22-23, so the next issue, the one 784 will be in, will be used for both week 22 of the magazine's year as well as week 23. They're called double issues because they cover two weeks, hence double issue. Don't confuse double issue with double chapter!