Hidden instruction not hidden in matrix display mode

I have an instruction for a question in a roster, which should only be shown if requested by the respondent.
If the roster is shown in sub-section or flat mode this is handled as expected:

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But if the roster is shown in matrix mode the full instruction is always shown:

image

Is this intended (why?) or a bug?

I would like to use hidden instructions in matrix mode questions to display lengthy explanations for certain users, but not for the majority of users who don’t need or wish to see these instructions.

Thank you.

This looks like a bug: I see no particular reason to prevent instruction folding for this situation.

A ticket has been created in the issue tracker:

Thank you @sergiy, if this could be fixed within the next two weeks or so, we could make good use of hidden instructions in the UN Women Generation Equality survey currently under preparation.
Thanks,
Klaus