This actually doesn't bother me at all, since I suspect that the reason these "dinner rolls" are used in these renderings of the Last Supper is that they show bread in a form that is easily recognized by viewers who may have no idea what unleavened bread looks like.
Rolls of bread in any depiction of the Last Supper are an obvious error. Regardless of when it was held, preparation for the Feast of Unleavened Bread, which lasted a week after the Passover night itself, required that all Jewish homes be cleansed completely of any type of leaven. Leavened bread just was not there that night.
After much study, I truly believe that the Last Supper and betrayal in the garden was on Wednesday night with the crucifixion on Thursday. That allows for the full three days and three nights in the tomb (The "sign of Jonah" in Matthew 12). We've been taught that the crucixion had to be on Friday because it was the day before the Sabbath. However, that week had two Sabbaths: in addition to the weekly Saturday Sabbath, the first day of Passover is always a Special Sabbath, and John uses those words to describe the day after Jesus died. So I believe there were two Sabbaths, back-to-back, Thursday and Friday.
Also, John says that the Jewish leaders would not enter Gentile buildings during Jesus' trial because they would become ceremonially unclean if they did. He says they had not yet eaten the Passover, which, if you believe his account (and he was there!) indicates that the Last Supper of the previous evening was a passover meal eaten early.
So, while Jesus, the Lamb of God, was dying a miserable death outside the city walls, priests and the religious leaders of the day were slitting the throats of sacrificial Passover lambs in the temple. They completely missed the point of the greatest event in human history.
Can you imagine the panic when darkness and earthquake interrupted the slaughter and the veil was torn in two?
Poetry. Pure poetry.