The docs call out the following...
"The InstanceType option is obsolete. It's replaced by the newer and more powerful InstanceTypes option in the aws:ec2:instances namespace. You can use this new option to specify a list of one or more instance types for your environment. The first value on that list is equivalent to the value of the InstanceType option that's included in the aws:autoscaling:launchconfiguration namespace that's described here."
"The instance types that are available depend on the Availability Zones and Region used. If you choose a subnet, the Availability Zone that contains that subnet determines the available instance types."
Consider updating the configuration through the EB CLI. Refer to
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