Can't fight Motherboard after defeating The Destroyer at mutliplayer.

[WARUMBERG]

tModLoader v0.10.1.1
Tremor v1.3.2.7
Dedicated server hosted locally

After killing The Destroyer it is impossible to kill Motherboard - it despawns either the second you spawn it or the second you hit it.
Despite that monsters keep dropping a lot of Motherboard summoning items - I looted about 40+ of them, at the same time I did loot about 5~7 The Destroyer summoning items counterparts.
Interestingly my world is a Crimson type, Expert mode, so Destroyer summoning items shouldn't drop at all in first place.

I think all other reports at the forum about "Motherboard despawning" sum down to this issue - monster drop Mechanical Worms to the players despite that they are in Crimson world.
On top of fixing just the summoning item drop I'd suggest to make Mechanical Brain summon The Destroyer if used in Crimson world, with a text message to player more-or-less like "This is Crimson world, You can't fight Motherboard in here! Here, have The Destroyer instead!" and vice-versa for those that use Mechanical Worm in Corruption world, as mitigation for all those confused players affected by wrong boss summoning item drops.