It appears that some people do not understand the word — transubstantiation —
trans = transfer
substantiation — substance
The substance of bread and wine are changed through Christ’s words to his Body and Blood on John 6. (And also changed by the priest’s words that repeat those of Christ’s in each and every Mass.)
Every word in John is there for a reason; he was writing theology after all the synoptic Gospels.
No...we understand it.
It's just not what the NT says is happening.