error in MAC address generation in file ./packaging/setup/plugins/ovirt-engine-setup/config/macrange.py caused possible generation of MAC address of illegal form, for example '00:1a:4a:1:f:ff'.
engine silently used different mac address range than required. If generated range was 00:1a:4a:1:f:00-00:1a:4a:1:f:ff, engine actually used range was: 00:00:1a:4a:1f:00-00:00:1a:4a:1f:ff.
Badly generated MAC addresses stored in vdc_option table (which were then moved to mac_pool_ranges table) were fixed in same manner as engine misinterpreted them for several years, to avoid sudden change. So after this change, your setup will use still the same range, but it will be reported and stored in DB correctly (see 'Consequence' part for demonstration, how is bad range fixed).
DB now contains MAC address in correct form, and every user is highly recommended to verify his/her setup, if it actually uses MAC address range he/she expects to be used. If there's something odd it can be easily identified; if MAC address has more than expected (by one or two) leading zeroes, then your setup contained an error, which was fixed. Please update your setup if reported MAC address range is not the one you want to use.