Cannon Mob don't stay in place

UNIT_FLAG_DISABLE_MOVE is a confusing flag; despite its name, it only applies to players and simply means "the player is no longer in the control of its movement".

For the chasing cannons issue, the only viable method I see is to use EventAI with ACTION_T_COMBAT_MOVEMENT on EVENT_T_SPAWNED

For the casting spell issue, one is tempted to think that creature_template_spells table from the database is enough to make a creature cast spells. The truth is that table has nothing to do with creatures' spells, it simply describes what spells are available in your action bar if you CONTROL that creature (mind control, for example). Please remember, in MaNGOS and all it's descendants, no creature will cast spells unless instructed to do so via scripting! All creatures, by default, can only do melee attacks (and have combat movement enabled). So, for the cannons to cast spell 36238, it is mandatory to script them (EventAI is the most simple approach).

INSERT INTO `creature_ai_scripts` (`id`, `creature_id`, `event_type`, `event_inverse_phase_mask`, `event_chance`, `event_flags`, `event_param1`, `event_param2`, `event_param3`, `event_param4`, `action1_type`, `action1_param1`, `action1_param2`, `action1_param3`, `action2_type`, `action2_param1`, `action2_param2`, `action2_param3`, `action3_type`, `action3_param1`, `action3_param2`, `action3_param3`, `comment`) VALUES
('2123300','21233','11','0','100','1','0','0','0','0','21','0','0','0','0','0','0','0','0','0','0','0','Prevent Movement'),
('2123301','21233','9','0','100','1','0','50','50','200','11','36238','1','0','0','0','0','0','0','0','0','0','Cast Fel Cannon Blast'),
('2246100','22461','11','0','100','1','0','0','0','0','21','0','0','0','0','0','0','0','0','0','0','0','Prevent Movement'),
('2246101','22461','9','0','100','1','0','50','50','200','11','36238','1','0','0','0','0','0','0','0','0','0','Cast Fel Cannon Blast');

Seems to work very well.  What do you think? @H0zen

PR has been made for both M1 and M2

Rel21_03_022