A firewalld bugfix update has been released for CentOS 7.

CentOS-announce: CEBA-2020:5014 CentOS 7 firewalld BugFix Update

CentOS Errata and Bugfix Advisory 2020:5014

Upstream details at :   https://access.redhat.com/errata/RHBA-2020:5014

The following updated files have been uploaded and are currently
syncing to the mirrors: ( sha256sum Filename )

x86_64:
e65c76e2da0feca843e2f481d8447767d71a1f723ceeca4f9720896b896a6e7e firewall-applet-0.6.3-12.el7.noarch.rpm
d247f05fd2f22a9dc59679f6c668b92c75b8f5beb481c99983a0b6d26d10bb08 firewall-config-0.6.3-12.el7.noarch.rpm
5c481b40303686e7be3e1c4fb48c29d0e1c8d41c8eec46b55771c7970af95954 firewalld-0.6.3-12.el7.noarch.rpm
c515fb742f9fbf6e205c91df3d75b991bc0e87b359f64d944d2e6930b0b37ce8 firewalld-filesystem-0.6.3-12.el7.noarch.rpm
237bcee37560d0ebf83c164ac3467d48d1c0e37558d2608e16c324a417061e16 python-firewall-0.6.3-12.el7.noarch.rpm

Source:
b7da7b09ca18913fccb9adeeb45b20970e52dd077676042101c0f57279acdcaa firewalld-0.6.3-12.el7.src.rpm