Excel Import of custom mandatory field doesn't work

[former_member642852]

I'm using Hybris version 6.7.0 and I stuck with the following problem: When I trying to perform importing products from excel file. It gives me the following error ->

I've checked the excel file and there is, of course, field "Subscription Term*", it is mandatory that's why there is an asterisk there. Good to mention that this field is custom, so I write custom translator to it and exporting part works fine, but in importing part when I did debugging I found strange fact:
This WorkbookMandatoryColumnsValidator validator calls the method findColumnIndex(typeSystemSheet, sheet, this.prepareSelectedAttribute(mandatoryField));from DefaultExcelTemplateService this method returns -1 and the validation does not passed. I dig into this method and there is such line of code: String attributeDisplayName = this.findAttributeDisplayNameInTypeSystemSheet(typeSystemSheet, selectedAttribute); which returns "Subscription Term" string as you can see without an asterisk.
I've checked the other mandatory fields e.g. "Catalog version*^" it returns with 2 symbols after it. The thing is that "Subscription Term" and "Subscription Term*" after string equality operation returns false and the validation fails as you can see here:attributeDisplayName.equals(this.getCellValue(headerRow.getCell(i))).
Of course the second value is taken from the excel file where the asterisk sign presents.
If I remove an asterisk from excel file then I receive: Unknown attributes of type ISku error in WorkbookTypeCodeAndSelectedAttributeValidator validator:

The asterisk should be presented in excel file, I've just checked what would be...
It doesn't help me at all to understand what really happens.

I can't understand one thing: What is the source of "Subscription Term" string? Why without an asterisk? Is it predefined constant somewhere?

From debug I couldn't figure out from which source that string comes from.