I raised it as an issue, since it’ seems squarely related to the terraform bug around it,
https://github.com/pulumi/pulumi-aws/issues/1504, almost like pulumi-aws behavior changed and doesn’t align with what the underlying TF code is expecting for setting the default version of the launch template. I’m kinda at a loss as to what would have changed there without extensive digging, but it seems like a problem.