I planted a bunch of OTs last year in early spring and we too had an abnormal spring. About 1/4 of them never came up. After many of the others were established, I went digging around the ones that never grew. The bulbs were all in good shape, so I just left them alone. This year they literally all came up (both the ones that grew last year and those that didn't).
Sorry I can't give a definitive reason as to why, just thought I'd share what happened to me.
