Iceman, SCaro I think you have it. The best explanation I saw of this phenomenon was Davies' discussion on the superstall, (in both the 2nd and 3rd editions, Handling the Big Jets, CAA, 1975):
P119: (b) The effect of the wing planform characteristics (sweep)
In practice the whole wing does not stall at the same instant. A simple swept and tapered wing will tend to stall at the tips first because the high loading outboard, due to taper, is aggravated by sweep back. The boundary layer outlfow also resulting from sweep reduces teh lift capacity near the tips and further worsens the situation. This causes a loss of lift outboard (and therefore aft) which produces pitch up. A lot of design sophistication is needed, including the use of camber and twist, leading edge breaker strips, fences, etc., to suppress this raw quality and get an inboard section stalled first so that the initial pitching tendency is nose down.
. . . . etc