all gitlab kubernetes runner failed with certificate problem

Yesterday at about 14:00 to 15:00 GMT all our gitlab kubernetes runners (14.10.1) failed and refused to run new pipelines at the same time. The message was

:
Getting source from Git repository
Fetching changes with git depth set to 50...
Initialized empty Git repository in /builds/example/modules/project/.git/
Created fresh repository.
fatal: unable to access 'https://gitlab.com/example/modules/project.git/': SSL certificate problem: unable to get local issuer certificate
:

I had to restart all runners to make them work again.

openssl showed that the certificate of gitlab.com was OK, but brand-new. A wild guess would be that the old cert chain was cached somewhere in the runner and expired at that time. Since the new cert on gitlab.com is valid for only 3 months we are concerned that this problem comes up again in August.

Would you mind to fix?