I use a CTC dual with mods. This issue just cropped up on last few long prints, and it is not a normal layer shift I have seen before where say something is loose or moves or skips during a print and the second half of the print after the shift is all built on top of the new layer. This was different.
On my last two prints, their was a shift in the x axis that seems to correct itself quickly. Image a wall with a V shape of layers that pertude out (backward on the X axis) for 3-4 layers gradually, and then back in for the next 3-4 layers correcting the shift and the print continues fine and the rest of the printed wall is aligned fine with the beginning all accept the “V” shape of 3-4 gradual layers out and then another 3-4 in correcting it (i.e. the V in the wall)
I hope that explanation makes sense. I dont see anything obvious loose, but I wanted to see if anyone has seen this or has any suggestions about what to check first?