Hey Eric, thank you for throwing light on this issue. It really helps.I saw that newer release has the fixed code.
Unfortunately,  I am not able to update it.
Seems my repo mirror does not have newer release yet.

[HOST ~]# yum upgrade openstack-designate-api
Repository 'CentOS-PowerTools' is missing name in configuration, using id.
Repository 'centos-messaging-rabbitmq' is missing name in configuration, using id.
Repository 'epel-boost' is missing name in configuration, using id.
Repository 'epel-nagios' is missing name in configuration, using id.
CentOS-8 - AppStream                                                                                                                                                                19 MB/s | 6.3 MB     00:00    
CentOS-8 - Base                                                                                                                                                                    6.1 MB/s | 2.3 MB     00:00    
CentOS-8 - Ceph Nautilus                                                                                                                                                           925 kB/s | 412 kB     00:00    
CentOS-8 - Extras                                                                                                                                                                   30 kB/s | 8.6 kB     00:00    
CentOS-PowerTools                                                                                                                                                                  4.5 MB/s | 2.0 MB     00:00    
elastic beats repo                                                                                                                                                                  84 MB/s |  20 MB     00:00    
centos-messaging-rabbitmq                                                                                                                                                          265 kB/s | 137 kB     00:00    
epel-boost                                                                                                                                                                         6.9 MB/s | 8.9 MB     00:01    
epel-nagios                                                                                                                                                                        3.4 MB/s | 8.9 MB     00:02    
ICINGA (stable release for epel)                                                                                                                                                   939 kB/s | 192 kB     00:00    
InfluxData Repository - CentOS 8                                                                                                                                                   377 kB/s |  30 kB     00:00    
Puppet 5 Repository el 8 - x86_64                                                                                                                                                   16 MB/s |  21 MB     00:01    
RDO CentOS-8 - QEMU EV                                                                                                                                                             1.0 MB/s | 177 kB     00:00    
OpenStack Train Repository                                                                                                                                                          12 MB/s | 3.2 MB     00:00    
Dependencies resolved.
Nothing to do.
Complete!



Already done yum clean all!