When I go to update the minimum number of instance and maximum number of instance then I got the following error.

Failed to update instance group xxx-instance-group: Internal error. Please try again or contact Google Support. (Code: ‘616599588FD78.937C2F2.7E0A7CE1’)

1. I tried to check another instance group that has some minimum and maximum number of instance just try to save it, getting the same error.
2. I tried to check my quota in the same region it is also within the limit