Which version of CRDB are you running? The most recent alpha should have this PR, which should skip over decommissioned nodes going forward and eliminate this issue.
Another way to put this: the fix for this issue should be out in 2.1, which will be released in October. In the meantime, we recommend sticking with a stable release (2.0.4 out, 2.0.5 upcoming).
Thank you , My CRDB is 2.0.4. Wait for 2.1 to arrive.