Error when using bicep parameter file not linked to a template

[ribeiroi]

dev.bicepparam:

using none

var environmentSuffix = 'd'

main.bicep file (basically blank, just setting the targetScope):
targetScope = 'subscription'

Running: az deployment sub create --location eastus2 --template-file main.bicep --parameters dev.bicepparam

Error: expected string or bytes-like object, got 'NoneType'

If I change using none to using 'main.bicep', then it runs without error.

Is this a bug?

[K4pper]

I have this exact same issue, would love for an answer on this