While playing morphtronics. i have come across a bug with De-Synchro  and Formula Synchron  .

Whenever i summon this card and use De-Synchro on it, it fails to resummon the materials even if both are in the grave.

I tested it vs ai and against myself and both times it failed.

I have attached a replay where i use De-Synchro
File Attachment(s):
De-Synchro Bug.yrp (1kb) downloaded 1 time(s).

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No deck is perfect from the getgo.
Not a bug. The reason you didn't get to re-Summon the Materials was that the Tuner (Smartfon) was Special Summoned by Celfon's effect rather than by its own condition. Since it was not properly Summoned, it could not be Special Summoned from the Graveyard. De-Synchro has to Special Summon either all of the Synchro Materials or none of them, and it could not Summon Smartfon, therefore it could not Summon anything.
Ah i see, totally forgot that some monsters need their own condition first, thanks for clearing that up 🙂
No deck is perfect from the getgo.