Nostalrius Begins - Quality wow vanilla realm (1.12)

This is common mangos bug seen on every private server. When playing warlock instant cast of "Corruption" with talent "Improved Corruption" 5/5 often can be interrupted by moving shortly after cast button pressed - i.e. press cast button, then move in any direction. This issue may be with instant cast of "Shadow Bolt" when "Shadow Trance" is active. This is caused because cast itself happens on server's time tick, but flag about spell interruption is set in network handler of moving data packets before time tick. Moreover, instant casts can be cancelled by counterspell, but it's less annoying then interruption by move in combat.