MrFrizzanswered grow question 4 years ago I had some male plants and this looks like a pollen sac to me; and yes probably it is stress induced.
Try pinch it off, if the plants hasn't shown any other signs of male preflowers, chances are its still gonna be female.
I had one that did the same, produce one single pollensack when it wasn't even ready for preflower and I just pinched it off - now female preflowers evreywhere!
Hope this helps and good luck!!