The only thing I changed is that I added output from some resources

This is strange, since the preview showed no changes. If you don't mind, can you run with

pulumi --logtostderr -v=9

and share the resulting logfile? (Only do this if there is no sensitive information in your config, this will dump lots of info, obviously not your AWS creds though.)

Mail sent

Closing the loop here - after an offline email follow-up, this turned out to be due to https://github.com/pulumi/pulumi/issues/1596.

I'll follow the conversation in the issue, thanks Luke