Hmm, I never actually noticed that. I wonder if that’s the intended behaviour, feels like a bug,
Here’s a quick hacky workaround, where we lock/disable the targeted data dams on the first canvas run, and then unlock/enable them again when the transfer button is pushed. This requires that the GhPython must compute first, which is solved here by sending it the back with Ctrl + B (see this great article):
241024_TransferDataDams_00.gh (8.9 KB)
Edit: Unlocking the dams appear to raise an expiration error when you first run the script. You can choose to ignore those warning and it should work as expected, but obviously we should code that out. I’ll have a look when I get a moment.