Text in group are changed by the frame size, IDK why?

After grouping the text and the rect, when I resize the size the text always auto resize itself, I am sure I did not group it with the frame, is it a bug or a technique problem?

Hey there, would you mind sharing a screen recording with us?

This problem

Apologies for the delayed response, @tkykaren233. Would you mind sharing a copy of your file so I can test this out myself?

Thanks! I’ve applied constraints to the groups, have a look at my screen recording below.
Also if you want to achieve a responsive design you can have a look at this YouTube video.