IncommensurableException error

[CzarMich]

Working with a CQL that has an expression that compares values that are greater or less as seen below. But I get an error where by the server is confusing two different units ´. ie. mmol/mol and μmol/L" of which my values do not have any μmol/L units except mmol/mol.

define NDH:
exists ([Observation: Code '4548-4' from LOINC] O where O.value as Quantity >= 42 'mmol/mol' and O.value as Quantity <= 47 'mmol/mol')

Error response from server:
{
"issue": [
{
"severity": "error",
"code": "exception",
"diagnostics": "Error while evaluating the expression NDH: javax.measure.IncommensurableException: mmol/mol is not compatible with μmol/L"
}
],
"resourceType": "OperationOutcome"
}

Could this be a bug on the server?