Marlin steps per mm changes during print.

Please excuse me if this is a common post, I tried searching for this error with little luck.

I have been using Marlin on my Prusa for two months now and rarely have any issues. I was calibrating my machine today and half way through the print, the X-axis started to half its steps per mm. The picture attached shows how the circle and cross turned into an oval more than 30% into the job. This has happened before, but all I did to resolve it was double my steps and it printed normal. Now it is randomly switching back and forth and I have no idea what is messing with it.

This same thing happened to me when using repetier-host firmware and software. Now I am using the non-install pronterface and a regular install of slic3r, and I believe the most current version of Marlin. I turned off EEPROM settings and I am using almost no acceleration, also using basic settings on slic3r.

My hardware is Arduino Mega R3 with homemade RAMPS board and standard A4988 drivers.

Check your jumpers/solders on your x-axis. Maybe it's switching from 1/8 stepping to 1/16. I don't think it's a software problem.

@ Kenzu, I think that might be the issue. Im going to replace all of the driver sockets and resolder the board in a day or two. I'll post an update after but thanks for the help!

The problem seems to have stopped completely now.