At reboot community-list entries are not visible in vtysh.
Adding new afterwards seems to work however.
But editing an existing does not work.

The issue seems to be in /opt/vyatta/sbin/vyatta-policy.pl
sub update_community_list

Editing a community-list begins with deleting the old one, so all changes and deletes are handled correctly.
But in FRR this is not possible.

(config)# no ip community-list 7
% Command incomplete: no ip community-list 7

You have to specify the complete line
no ip community-list 7 permit 65001:123

So this i cannot easily try a fix, we need to now the existing rules, or work through the changes.

The manual shows that it should still be possible.
no ip community-list [standard|expanded] NAME
http://docs.frrouting.org/en/latest/bgp.html#miscellaneous-configuration-examples

But the running FRR 5.1-dev in this image only had the following;
(config)# no ip community-list 7

deny    Specify community to reject
permit  Specify community to accept