CaptionClass and missing Tooltips in CardPart Pages


We have an issue with tooltips when displaying a field in a CardPart page. Let's take for the sample a field in the factbox that is calculated in runtime with a procedure:

            field("Run Time"; GetRunTime())
                ApplicationArea = All;
                CaptionClass = 'TR,RUN_TIME';
                ToolTip = 'Specifies the run time of the operation.';
If we use captionclass property, then the tooltip of the field is not shown, as you can see in the following capture:
If we use a Caption instead the captionclass the tooltip is shown (but we cannot use Caption in some cases)

Is there any issue related to this? Can we use captionclass in the page and get the tooltip somehow?

Thanks in advance!