Has anybody encountered such an error and if yes how can it be avoided in the future?

10 gms servers, 6 on sles11 4 on sles12, same gms version 14.2.2 Build: 195
4 eDirectory server combined with NetIq LDAP Proxy as source for GMS.
Users are added to GMS via eDirectory groups.

On a nice winter day all 4 eDirectory servers encountered a fatal error and went down roughly about the same time. Every gms server noticed the outage and removed every user from every GMS server. After the eDirectory servers came back GMS noticed the users in the groups and added them back. This caused about a 12 hour downtime in the service.

So how can I prevent GMS to remove users when it cannot reach eDirectory?