The file was exported using the DNxHD MXF OP1a format with a preset that uses the 440 family.
This issue occurs only in Media Encoder version 7.0.1
Solution 1: Reencode using another preset, such as 220. This issue only affects DNxHD presets in the 440 family.
Solution 2: Encode using the QuickTime file format with the DNxHD codec.
Solution 3: Install Adobe Media Encoder 7.0 (CC) on a second computer and choose not to update this installation.
Note: Adobe Premiere Pro CC 7.0.1 is available and does not have the issue importing these files. However, After Effects CC 12.0 cannot import DNxHD MXF 440X files encoded through Adobe Premiere Pro CC 7.0.1.