corner issue on calibration cube

[jram]

Hello All,
I recently relocated my printer to the place I teach and I am now having a small issue. I have spent the past few days tracking down filament starvation issues that were not there before I moved the printer. I have slowed my print speed down to 25mms for everything and "reseasoned" my E3d v6 as I suspected some type of resistance in the bowden tube to be the culprit. This seemed to eliminate the voids in the print so I think I have solved that.. Now I am getting this small crunched in area on my 20 mm calibration cube between two towers. Any ideas on what may be causing this? I recently had the hot end off because it loosened over time. It seems that my E3d does this every 600 hours or so.

Print settings
Nozzle 0.4
ABS @ 225, Bed 85
Speed 25mms
retraction 1.2mm

[jram]

Hello All, I have solved the issue with the corner. Hopefully this will be of help to someone. I initially thought that it may be a hot end clog or loose hot end so I worked through the entire hot end with no change.. After days of tinkering, I decided to check belt tightness and found that the belts were also fine. While I had the plastic covers off of the top and bottom of the machine, I found that the bolts that secure the towers were all loose! It's almost as if the MDF panels contracted and left slack in the nut.
I have never had this happen as I check the machine regularly. I recently moved the machine in to a studio with a ceramic kiln, I am wondering if the air in the studio is dry enough to change the dimensions?.. After tightening, the machine is printing just as before with no ridges or funky corners.