Plants Fighting?

I have these two plants growing together. Ahawaska purple, (I know I spelled that wrong..crazy name), and Maui Waui.
The Maui is dying. The purple is doing fine. I'm not desperate to save the Maui. Just trying to understand.
Could the Purple be killing the Maui?
Checked the PH. Running around 6.0.

Damn if one my plants has the same bottom stem. Moving away from the faster growing plant in veg. After the flip. The slower plant stretched past the first to pisil up plant. By 4" over canopy level.

I'm going to have to feed her separately from her sister.

Fight? Probably. More weight.

You could be right. I actually pulled them over to move them from the lights. I've done this several times . Even with tomatoes and such.
I've never had this problem before. The roots are not that deep so I believed I wasn't breaking anything. But ....oh well live and learn.
The purple is much bigger. Really flowering up.
It's a clone given to me. I was told it flowers early. 50 days.