When i use brilliant fusion and summon Gem-Knight Seraphinite and use it's effect to n.summon 2 monster the effect of Drei to become lvl5 doesn't active, neighter being the first or second to be summoned. Oh, and i tried with another monster that's not require the n.summon to active the effect( i mean, only requires to be in the field) and they work fine

Theres any restricion a i didn't realize? or it is a bug?
Cyber Dragon Drei
When this card is Normal Summoned: You can make all "Cyber Dragons" you currently control become Level 5. You cannot Special Summon any monsters during the turn you activate this effect, except Machine-Type monsters. If this card is banished: You can target 1 "Cyber Dragon" you control; it cannot be destroyed by battle or by card effects this turn. This card's name becomes "Cyber Dragon" while it is on the field or in the Graveyard. 
Ok, but i was testing again and i realize if u n.summon the Drei on 2nd phase at same turn it's effect work perfectly and i can summon Nova normally, and it's propertys says u could not summon at same turn
Just tested this myself and I could not use the effect, as I should not be able to do.

If you are able to use the effect in this scenario please post a replay showing the effect activating, and please state on which server and game version this occurred.
My current version is 1.033.7 V2 Percy.( check in download link and it's supose to be up to date)
I was testing against the AI, none server duel because it was a my intention to test the move.
And after u show me i start to thought that it's not a negative bug ( for don't let u use Drei effect and summon another monster) but it's a positive one, because let u summon 2nd phase and avoid oponnent turn. What u think?