invalid recognition on special Methyl-included compoud

[biotech7]

for example:

String structStr= "Methyl (R)-1-(2-(ethoxycarbonyl)-1-phenylallyl)-6-oxo-1,6-dihydropyridine-3-carboxylate (3pa): the 
reaction was conducted.....";
Oscar oscar = new Oscar();
List<ResolvedNamedEntity> nameEntities = oscar.findResolvableEntities(structStr);
for (ResolvedNamedEntity ne : nameEntities) {
     String name = ne.getSurface();
     System.out.println(name);
}

expected name: Methyl (R)-1-(2-(ethoxycarbonyl)-1-phenylallyl)-6-oxo-1,6-dihydropyridine-3-carboxylate
actual name: (R)-1-(2-(ethoxycarbonyl)-1-phenylallyl)-6-oxo-1,6-dihydropyridine-3-carboxylate

Development Environment：
IDE: IDEA
JDK: 1.8
OSCAR: OSCAR4-5.2.0

[mjw99]

I can reproduce this issue via the webapp demo