My Ubiquiti 3Ghz cards stop connecting to each other after 6.9
has any one else had this issue and is there a fix?

After 6.9???

6.18 is out, have you tried it?

You have two choice: replace 3GHz Ubiquiti cards with some compatible with 6.18
or still on RouterOS 6.7

Yes I have tried the newest release 6.18 but still no luck