I've noticed a serious bug in effect opcode 122 (Create Inventory Item) which is triggered when using timing mode 0 (Instant/Limited).
If you are specifying a duration of 256 or higher, the effective duration is reduced to a few seconds up to a few minutes in the game, depending on the given duration. For example, a duration of 256 is reduced to about 15 to 20 seconds. Both BGEE v1.3 and BG2EE appear to be affected.
Furthermore, if you place the created item on the ground and pick it up again, the timer is cancelled and the item will only disappear after resting.
I have put together a small mod
to demonstate this behavior. After installation, create a scroll via game console:
and use it to create an inventory item. The duration of the item is set to 256 seconds (4m16s). In BGEE and BG2EE it will disappear after 15 to 20 seconds however. In the original BG2 it will remain for the full 256 seconds.