Fred has "nonqualified use" of his principal residence that will reduce the exclusion on the gain on a sale of a personal residence.
Explanation:
Fred moved into his house post a period of “nonqualified use”. Nonqualified use can be stated as any period during which the particular asset is not used as the primary residence of the owner or taxpayer.
If a taxpayer moves between two houses, using each as his residence for consecutive periods of time, the home that the owner uses for most of the time will be stated as the person's principal residence.