wrong work with property names in newer 4's

[OCsite]

Hi there,

after upgrading to 4.11, our code stopped working. Eventually I've succeeded to 
isolate the problem — looks like it is not able to properly distinguish a 
property foo and a method isFoo anymore:

===
147 ocs /tmp> <q.groovy                                   
class Foo {
    int ndx
    def opened=[] as Set
    boolean isOpened() {
        ndx in opened
    }

    static void main(String[] args) {
      Foo f=new Foo()
      f.opened<<3
      for (int n=0;n<5;n++) {
        f.ndx=n
         println "OP "+f.isOpened()
      }
   }
}
148 ocs /tmp> /usr/local/groovy-4.0.0-alpha-1/bin/groovy q
OP false
OP false
OP false
OP true
OP false
149 ocs /tmp> /usr/local/groovy-4.0.11/bin/groovy q       
Caught: groovy.lang.MissingMethodException: No signature of method: 
java.lang.Boolean.leftShift() is applicable for argument types: (Integer) 
values: [3]
groovy.lang.MissingMethodException: No signature of method: 
java.lang.Boolean.leftShift() is applicable for argument types: (Integer) 
values: [3]
        at Foo.main(q.groovy:10)
150 ocs /tmp> 
===

Thanks,
OC