Swiftkey refuses to learn the word "shaft"

I was trying to write out drive shaft and no matter what I do I cannot get swiftkey to work with the word shaft.

If I type shaft out and select it, it will then work when swyping.  But if I delete the word shaft it will no longer put it in when I swype.  I have tried removing EVERY other option that come up and it does not help.  No matter what I do I can not get shaft to work when swyping unless I manually type it in first and leave it there.

I tried manually typing it out many times in a row and tapping the correct word down in the predictive text box but that does not help at all.

This is very aggravating, I am open to any suggestions.