I could find a few references to this issue but not a bug report post, so here it is.
Flying from a fixed runway on Nevada, unless the AI is light enough to take off almost vertically, the nozzle use causes them to be unable to take off, and after initially accelerating, they end up sat firm on the runway, with the engines on maximum and nozzles back.
By reducing significantly the takeoff weight, the problem is fixed, however this leaves AI harriers unable to take off with effective stores.
I've been able to replicate in different missions and with different AI competency levels.