Text background colour looks misaligned in slideshow mode

I use text background colour to create text boxes that 1) resize dynamically if I edit the text 2) can be overlaid on images so that I don't have to worry about legibility of content.

I set text background colour as white, and to make sure paddings look nice, I adjust with baseline shift, before/after paragraph spacing and add a <space> before and after the label.

The issue is that when I present my slides (aka. play slideshow), the padding of the text background colour is misaligned.

I found a workaround, which I have used for years: grouping the text boxes with other items fixes the issue. But still, this is probably a bug that should be fixed.

However, when I want to create a slide layout (master slide) and set those text boxes as placeholders for Title and Body, grouping doesn't work. Hence, the bug persists.

Do you have any recommendation on how to solve this issue on Slide layouts? Also, how can I report this bug?