[ic] theme.cfg irreversably altered by the Admin UI?

[Hostmaster]

Hello List Members,
IC 4.9.3 on Linux 9.0

After modifiying the theme.cfg on my local computer, I imported it using the
import feature of the UI.  It worked perfectly.  Then I changed a product
group heading using the "Design" feature of the UI, after which the
formatting of the text reverted from size 14 to the default (I believe it
was 11 or 12px).

To try to get it back to where I had configured it, I re-imported the
theme.cfg file using the Admin UI, the same way I did initially.  I clicked
on "Apply Changes" just to make sure.  When it didn't make the change, I
cleared my browser cache.

But the product group heading did not change.  Is there a bug when using the
UI to configure the product group headings that overwrites the imported
theme.cfg file permanently?

Best regards,
Michael G.