With CTMod 2.0 and CTRA 1.62, if I summon my Water Elemental while in combat, the pet interface doesn't appear.
If only CT_UnitFrame is loaded I don't have the bug. It occurs only if CT_Core 2 is loaded or CTRA 1.62.
Several add-ons seem to have this bug. For example GuildEventManager (GEM) 2.21, corrected in 2.22 (
http://christophe.calmejane.free.fr/wow/gem/).