The quote does say "almost evening", though. Almost evening is also known as eventide. It precedes sunset.
Here's Justin the Martyr
"For it was not without design that the prophet Moses, when Hur and Aaron upheld his hands, remained in this form until evening. For indeed the
Lord remained upon the tree almost until evening, and they buried Him at eventide; then on the third day He rose again."
ANF01. The Apostolic Fathers with Justin Martyr and Irenaeus | Christian Classics Ethereal Library (chapter XCVII, (97), Dialogue with Trypho)
Here's Exodus 17:12 to which he refers:
KJV: But Moses' hands [were] heavy; and they took a stone, and put [it] under him, and he sat thereon; and Aaron and Hur stayed up his hands, the one on the one side, and the other on the other side; and his hands were steady until the
going down of the sun.
NIV: (getting one right

) till sunset
NASB: until the sun set
YNG: till the going in of the sun
Justin Martyr on the same verse:
almost until evening.
He and I (don't know about you folks) know what that means. Sunset. Sun has gone in/down. The day is over. A new day has begun. Clearly he KNOWS this. How do we know he knows it? Because he CHANGES it to read: ALMOST until evening.
The word, the idea, the concept of ALMOST is NOT there in scripture. If it was there, Justin would not need to add it. But he does add it. Why? He does it to conform to Tradition.
Now, if he had adhered to scripture, then it implies, according to the same well-known Tradition, that Christ was buried on Saturday/Sabbath. Clearly that is wrong. He was in fact buried on Friday/preparation day. Therefore, what? He must have died on Thursday/passover.
"It was by design" that Moses' hands were held steady until the going in of the sun. The NT tells us exactly the same story.
Tradition is wrong. Scripture is right.