Asus RT-AC86U - Out of memory / Settings don't save / Log "Argh. No free space left for GC."

Hi Everyone

I often dip in and out of SNB to research and solve my own problems but I am really struggling with this one.

I noticed certain settings that I was adding were just not saving (port forwarding etc...) and checked the logs which are repeatedly filling up with something like this.

Jan 12 11:29:26 kernel: jffs2: Argh. No free space left for GC. nr_erasing_blocks is 0. nr_free_blocks is 0. (erasableempty: yes, erasingempty: yes, erasependingempty: yes)
Jan 12 11:29:26 kernel...

Asus RT-AC86U - Out of memory / Settings don't save / Log "Argh. No free space left for GC."