end trace error after 400 boot sequences

I want to use a Rappberry Pi to control a machine with Ethercat.
My sd card partistions are mounted read only.
After 460 times hard power off, i get a end trace error.
After a restart everything works fine.
Can anyone say what the end trace error 3 means and why it occours?
Because my file system is read only i only have a picture of the error.
Error:
https://drive.google.com/file/d/1p67...ew?usp=sharing
Standard boottext:
https://drive.google.com/file/d/1Xr2...ew?usp=sharing

Thanks for your help.

That's in errno-base.h in /use/include/somewhere/. I trust you to run it down, because I am on a tablet.