incorrect Pattern.CANON_EQ handling

ADDITIONAL SYSTEM INFORMATION :
Windows & Linux

A DESCRIPTION OF THE PROBLEM :
Exception in thread "main" java.util.regex.PatternSyntaxException: Unmatched closing ')' near index 31

REGRESSION : Last worked in version 11.0.15

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
java Main

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Console output: "Result: true"
ACTUAL -
Exception in thread "main" java.util.regex.PatternSyntaxException: Unmatched closing ')' near index 31
^\s*(ИП|Индивидуальны(?:и?)|й)|и)?)\b.*$
                               ^
        at java.util.regex.Pattern.error(Pattern.java:1969)
        at java.util.regex.Pattern.compile(Pattern.java:1706)
        at java.util.regex.Pattern.<init>(Pattern.java:1352)
        at java.util.regex.Pattern.compile(Pattern.java:1054)
        at Main.main(Main.java:7)

---------- BEGIN SOURCE ----------
import java.util.regex.Pattern;

class Main
{
    public static void main(String args[])
    {
Pattern p = Pattern.compile("^\\s*(ИП|Индивидуальный)\\b.*$", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE | Pattern.CANON_EQ);
System.out.println("Result: " + p.matcher("Индивидуальный предприниматель").matches());
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
It will work, if I remove Pattern.CANON_EQ flag

FREQUENCY : always