227. The first incident relevant to the ceasefire reportedly took place on 23 June 2008, when a 67-year-old Palestinian civilian was injured when the Israeli military stationed at the border
north-west of Beit Lahia opened fire on a group of Palestinians trying to collect fire wood near the border. Also on 23 June, two mortar shells were reportedly fired from central Gaza. One landed near the Nahal Oz crossing and the other in the Negev desert; no injuries were reported.
YNet reports a mortar shot "early Monday morning" while Ma'an reports that the Palestinian Arab man was injured on Monday afternoon.
So which was the first incident? Apparently, the Goldstone Commission can't figure that out.
Interestingly, when Islamic Jihad shot three rockets to Israel on June 24th, they didn't claim it was in reaction to any Israeli actions in Gaza, rather for something the IDF did in Nablus. So it is entirely possible that the report of the 67-year old man is less than accurate.