When a member joins from another legion where they have been helping with the base in the legion they came from and they try to contribute to their new legions base they are unable to and get the message, "Cannot upgrade. You have contributed to a different base in the past week."
I'm taking this to assume they must wait a week before being able to contribute to the legion base, but they only have to be in the legion for 24hrs before they're getting an even share of the base's production.

They should be able to contribute to the legion base within 24hrs of joining the legion even if they have previously helped with a different base before joining.

This is by design.

i thought that, this should probably be in the suggestions section now i've thought about it, but why should they be getting a share of the resource when they can't contribute

I agree, you should be in a legion a week before getting the production

So you want the option between Divided Evenly Between all Eligible Members and Divided by % of Base Upgrade Contributions so something like:

Divided Evenly Between all Contributing Members

I can see that, it does make sense.

+1 to that. Even with the low chance that anyone in my legion would have to deal with it, that is how I would want it to work.

Maybe as a third option only
a) percentage by contribution
b) equally by those who contributed - even gold
C) equally to all legion members

And is a week really long enough to discourage the legion hopping?