BuddyPress.org

Hi,
I run a site: http://rohamjelvenyek.com/, WP 4.4.1, BBPress 2.5.8, BuddyPress 2.4.3, Enfold theme.
The last week 2 strange thing happened:
1.
A user: who was moderator of the site for a long time, has disappeared from users, and all his forums become visible on the site under the name: anonymus.
As admin I did not do anything with this user before this happened, I only made the WP and plugin updates for the site. The user says, he did not deleted his account either.
2.
Yesterday (after 10 day of updating the site) another user who was moderator of the site for a long time, has disappeared, but at this time, his forums become visible under another user (a moderator) ‘s name.

What is very strange for me, that the issue happaned twice, but not the same way and time, and that the other 21 moderators have no problems, are not deleted.

I use a plugin: User Roles and Capabilities, maybe this caused the errors? But I cannot regenerate the issue on a test user, because I dont know, why exactly the users disappeared.

Please help me, I am afraid of other moderators will disappear also.
Thanks