Guided Editor doesn't work with 'contains' and 'excludes' operators

Description of problem:
After a slight modification of mortgages model, it is possible to build a fact pattern using contains operator like this:

$is : IncomeSource( )
Applicant( incomes contains $is )

However when a .rdrl rule with this source is open, it is displayed incorrectly.

Version-Release number of selected component (if applicable):
ER1

How reproducible:
-

Steps to Reproduce:
1. modify mortgages model (add 'incomes' field of type 'IncomeSource [0..N]' to Applicant)
2. create new Guided Rule and build the fact pattern from Description
3. save the rule, close it, open it again

Actual results:
The field name 'incomes' is missing and select boxes for operator 'contains' and bound variable '$is' are reset.

Expected results:
The result after re-opening the rule should be the same as it was saved:

There is an Applicant with:
incomes [contains] [$is]

Additional info: