I am working on a mipsel binary in IDA Pro and I'm having some issues with renaming subroutines.

I have the subroutine "system" at 0x739644. I renamed this using the N hotkey.

Now if I hit X, some of the xrefs have been replaced:

All of the JALR instructions are fine.

However, sometimes subroutines are called like so:

In this case, sometimes the reference has been renamed and sometimes it hasn't. They all show up in xrefs though:

Why is this? Can I rename them all?