Not really sure what I've done, was just checking combinations of crops. Crashlog below.
crash-2019-02-27_20.10.32-client.txt

Edit. Recreated this crash, happened at the same action, while trying to check 2 oil berry breed results, 3rd oilberry appear in crop windows and then game crashes, second crashlog included.
crash-2019-02-27_20.47.22-client.txt

Happened 3rd time, this time no 3rd crop appearance, crashed while checking results of oilberries breed.
crash-2019-02-27_21.34.43-client.txt

And again, with different crop, iirc fertilia, seems to occur when checking results of given crosbreed too fast.
crash-2019-02-27_22.15.40-client.txt

Plugin version: IC2+Nei+Plugin+Version+1.7.10-1.2.1

ok these are all the same crash and i wonder why that is happening because this is a impossible crash with ic2exp alone. I can not reproduce this.
The only way this could be achieved if someone deletes all crops and adds less then 9 options to it.
Could you provide a screenshot of your ui (before the crash) @bedrill64 ?
Edit: a video would be better. So i can see exactly how you made this crash.

I do not have software to create proper video, So, those 2 screens below are screens in which crash happened for me, as I move mouse cursor at results to check it game crashes with crashlogs I gave you above.

ok thanks this actually explains why there is a crash, because i assume that the output should also have at least 9 crops if that is not given there is no wonder that it crashes...
will be fixed within the next 10-20 min as of writing this message

9 minutes late. But submitted