  Newly-discovered superconductor UTe$_2$ is a strong contender for a
topological spin-triplet state wherein a multi-component order parameter arises
from two nearly-degenerate superconducting states. A key issue is whether both
of these states intrinsically exist at ambient pressure. Through thermal
expansion and calorimetry, we show that UTe$_2$ at ambient conditions exhibits
two detectable transitions only in some samples, and the size of the thermal
expansion jump at each transition varies when the measurement is performed in
different regions of the sample. This result indicates that the two transitions
arise from two spatially separated regions that are inhomogeneously mixed
throughout the volume of the sample, each with a discrete superconducting
transition temperature (T$_c$). Notably, samples with higher T$_c$ only show a
single transition at ambient pressure. Above 0.3 GPa, however, two transitions
are invariably observed in ac calorimetry. Our results not only point to a
nearly vertical line in the pressure-temperature phase diagram but also provide
a unified scenario for the sample dependence of UTe$_{2}$.
