Tested on 7.0.2 6645
Not sure the exact step to reproduce it.
Performed some testing on this build where Enforce TLS was enabled.
Now stop the Couchbaseserver and uninstalled it from control panel.
Progress of uninstalling started rolling back and CB server not uninstalled.
Tried to repair it but after repair also not able to uninstall it.
To recreate the Issue I tried to install fresh build 6653 with Enforce TLS and uninstall it and it uninstalled without issues.