Cortex question, am I doing something wrong?

For anyone who owns a cortex doll, I have a question for you, if you don't mind. I'm having issues with my dear Gaia's upper arms that I'm unable to figure out. I'm confident all the pieces are fitting nicely together, however when I put her lower arms in they push the upper arms apart at the seams.

Any idea what I'm doing wrong? It's when I bend her elbow that the lower arm puts the most pressure on the seam and it's only a matter of time before it pops right off. I considered gluing it of course, but if it's a construction problem I don't wanna ruin my chances to fix it.

All pieces accounted for.

Fits well.

All the little internal bits line up nicely.

Seam sits perfectly without the lower arm.

Inside the upper arm.

Lower arm in, already you can see pressure on the seam.

After bending the elbow a few times its nearly fully popped out.

Any insight would be greatly appreciated! She is a final boss grade kit, so its probably something silly I've missed.

And it does it click into place?
I think people have said it is common for their cortex parts to pop out like that every now and again.

So glue might be the only option if you want it secured.

However, before you consider gluing, I think you should test to cut these:



Edit:
Also.
Have you tried to put the arm together, with the "upper panel" piece left for last? Maybe then you can see if the "interior" has moved out of place, before you close it up.
 

Edited November 14, 2019 by Yumeiro

5 hours ago, Yumeiro said:

And it does it click into place?
I think people have said it is common for their cortex parts to pop out like that every now and again.

So glue might be the only option if you want it secured.

However, before you consider gluing, I think you should test to cut these:



Edit:
Also.
Have you tried to put the arm together, with the "upper panel" piece left for last? Maybe then you can see if the "interior" has moved out of place, before you close it up.
 

Thank you for the response!

In the end I had to just glue them. Multiple people said they noticed the same thing and gluing them was the best fix. I guess it makes sense, they were always intended to be glued together. I just like to tinker, lol.

I'm happy to report that the glue did work perfectly though!