Unable to modify local user group membership with forcelocal

Puppet Version: 5.4.0
Puppet Server Version: 5.2.0
OS Name/Version: RHEL 7

Breaking Change: https://tickets.puppetlabs.com/browse/PUP-8223

I also validated this is broken when using a puppet apply with this code.

group { 'group1' :

 ensure => present,

 gid => '901',

 forcelocal => true,

 }

group { 'group2' :

 ensure => present,

 gid => '902',

 forcelocal => true,

 }

user { 'user1' :

 ensure => present,

 home => '/home/user1',

 uid => '900',

 gid => 'user1',

 comment => 'user1',

 shell => '/bin/bash',

 forcelocal => true,

 managehome => true,

 groups => ['group1', 'group2'],

 require => Group['group1', 'group2'],

 }

So far I have found two issues.

1) lusermod does not support -G

1. lusermod --help
   Usage: lusermod [OPTION...] user
   -i, --interactive prompt for all information
   -c, --gecos=STRING GECOS information
   -d, --directory=STRING home directory
   -m, --movedirectory move home directory contents
   -s, --shell=STRING set shell for user
   -u, --uid=NUM set UID for user
   -g, --gid=NUM set primary GID for user
   -l, --login=STRING change login name for user
   -P, --plainpassword=STRING plaintext password for the user
   -p, --password=STRING pre-hashed password for the user
   -L, --lock lock account
   -U, --unlock unlock account
   --commonname=STRING set common name for user
   --givenname=STRING set given name for user
   --surname=STRING set surname for user
   --roomnumber=STRING set room number for user
   --telephonenumber=STRING set telephone number for user
   --homephone=STRING set home telephone number for user

Help options:
-?, --help Show this help message
--usage Display brief usage message

2) the new code will not "modify" the user's groups in /etc/group because the user already exists.

Desired Behavior: 
user type allowed to modify local users groups

Actual Behavior:

Error: UID 900 already exists, use allowdupe to force user creation

 Error: /Stage[main]/Localusers::Identities/User[user1]/groups: change from to 'group1,group2' failed: UID 900 already exists, use allowdupe to force user creation