Why PageFilter returning less rows than it should be?

[神之疯神]

Here's my code:
Scan sc = new Scan();
sc.addFamily(c);
FilterList flo=new FilterList(Operator.MUST_PASS_ONE);
flo.addFilter(somefilter);‍FilterList fla=new 
FilterList(Operator.MUST_PASS_ALL);
fla.addFilter(somefilter);‍FilterList fl=new FilterList(Operator.MUST_PASS_ALL);
fl.addFilter(new PageFilter(100));‍
fl.addFilter(fla);
fl.addFilter(flo);
                                sc.setFilter(fl);
                                sc.addFamily(c);
                                sc.setStartRow(lastrow.getBytes());‍



1480‍
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Michael.Calvin.Insighter.Shi
 神之疯神
 石梦珂