Hmm, this is difficult to debug as it would require a real donation and a bankheist to be running at the same time.
Now I know this isn't ideal but next time you are streaming ask someone (who is willing of course) to donate while you have a bank heist going then make a screenshot of the results. The only other thing would be to check if the donation was actually made. Did a popup appear in your stream? Did it record the donation that was made?