SimpleValidator doesn't allow intermediate CA certificate with PathLen:1'

FULL PRODUCT VERSION :
java version "1.6.0_18"
Java(TM) SE Runtime Environment (build 1.6.0_18-b07)
Java HotSpot(TM) Client VM (build 16.0-b13, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
The following chain returns a ValidatorException with the message "Violated path length constraints" in 1.6.0_18.

2010-01-29 13:49:20,219 INFO [http-127.0.0.1-8080-1] STDOUT:152 chain [0] = [
...
[8]: ObjectId: 2.5.29.19 Criticality=false
BasicConstraints:[
  CA:false
  PathLen: undefined
]


2010-01-29 13:49:20,266 INFO [http-127.0.0.1-8080-1] STDOUT:152 chain [1] = [
...
[6]: ObjectId: 2.5.29.19 Criticality=false
BasicConstraints:[
  CA:true
  PathLen:2147483647
]


2010-01-29 13:49:20,329 INFO [http-127.0.0.1-8080-1] STDOUT:152 chain [2] = [
...
[8]: ObjectId: 2.5.29.19 Criticality=true
BasicConstraints:[
  CA:true
  PathLen:1
]


2010-01-29 13:49:20,360 INFO [http-127.0.0.1-8080-1] STDOUT:152 chain [3] = [
...
[8]: ObjectId: 2.5.29.19 Criticality=false
BasicConstraints:[
  CA:true
  PathLen:2147483647
]

The problem occurs because the PathLen constraint in chain[2] has the value 1 and there is a CA certificate (chain[1]) that follows this certificate in the chain.

The specification says the following about the PathLen constraint: "it gives the maximum number of CA certificates that may follow this certificate in a certification path", so the chain should be accepted.

The problem only occurs in update 18.


REPRODUCIBILITY :
This bug can be reproduced always.

Release Regression From : 6u17
The above release value was the last known release where this
bug was not reproducible. Since then there has been a regression.